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Parker/Eurotherm 514C/507 4Q SSD DC Retrofit into 1961 10EE Modular

everettengr

New member
My 10EE came with an obsolete and badly matched solid-state drive that had a speed range of only 600-1000 RPM. It had little or no effective feedback control, meaning it slowed heavily even with moderate cuts. I knew my 10EE had been able to do much better on the Argon-thyristor 'Modular' drive, so I attempted to restore that.I was not able to make it fully functional. Eventually, I got tired of chasing gremlins and gave up to try a newer and better solid-state DC drive.

I made the decision to keep the DC motor in lieu of AC/VFD because DC motors and controls offer distinct mechanical advantages for a lathe compared to AC motors. Torque and speed are controllable independently and over the entire range from zero to maximum ratings (torque proportional to current supplied, speed proportional to voltage). This is well-matched to lathe applications, where various speeds-and-feeds requirements reflect back to the prime mover as motor speed and torque requirements.

Peak and short-term delivered power can be multiples of the continuous rating. This is also well-matched to machining, with short periods of heavy cutting interspersed with lighter cuts.

While a DC motor has nominal, or “nameplated” HP and torque ratings, it can deliver and sustain multiples of that power for short periods, subject primarily to heat dissipation and mechanical limits. A 5 HP DC motor can replace a stock AC motor rated from 7.5 to 10 HP. The DC motor control converts the AC input power to a variable voltage and current-limited DC supply, typically through a switched rectifier design.

For all their advantages, DC motors are not used as much these days for machine tools because the motors themselves became too expensive. Brushed designs also require periodic maintenance for brush inspection and replacement and commutator refinishing.

However, in my case, I already had the DC motor and was advised that new-old-stock SSD drives are very affordable, so why convert to a less advantageous AC design???

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everettengr

New member
What was changed

A little over a year ago I discussed with Bill (Monarchist) DC drive options. He provided a design approach basically ‘right out of the book’ for the Parker/Eurotherm SSD series of DC drives using full-isolation boost transformers and SSD’s own recommended addition of a large ripple-smoothing choke.

After delaying for while (~1.5 years), I have finally implemented this approach over the last few months.

Along the way to completion the initial tests with a very smooth 514C-16 revealed a bad vibration. Bill encouraged me to tear down the motor, clean up the commutator, replace bearings and brushes, and I also decided to replace backgear bearings, belts and mount isolation bushings. It was not until then that I discovered a badly bent brush holder, oddly worn brush, and damage to the commutator that had all been preventing any form of DC Drive from working well. While I had the motor apart, I added a salvaged tachogenerator.

The extra care was worth it. I now have a fully functioning DC 4Q SSD drive that freaking rocks!

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everettengr

New member
How it was done

A Eurotherm-Parker-SSD 514C is used for the armature/series field and a separate SSD 507 is used to excite the shunt field. The SSD 507 also provides control of shunt field weakening to obtain speed above the ~1150 RPM base to my max of 3000 RPM with the GE Kinamatic 5 HP motor.

The 514C is a 4-Quadrant or 'regenerative' drive, meaning it provides active drive and braking in both the forward direction, in the reverse direction, and also active braking to a stop. The 507 is a 1-Quadrant motor drive. It does not need to brake or reverse in this use.

I am using a 514C-16 which is only rated for 16-amp full load current. The motor I have calls for more than that - 18 FLA. The 16 Amp capable 514C-16 “should really have been” a 32 Amp-capable 514C-32. In spite of the apparent shortfall, we have made the less-costly unit work, and work very well, by pushing the available input voltage up into a range that gives it a bit more headroom, then using its option of allowing up to 150% overload (24 A) for 60 seconds each time called on.

The AC input to the 514C is from the 300VAC center tap of my big T-5 transformer as used in 10EE Modular drives, A second 2 KVA 32 VAC boost/buck transformer was added, wired as full-isolation. The transformer primaries are wired in parallel and the secondaries in series with polarity connected for boost. The combined transformers provide 332 VAC input to the 514C-16 DC Drive.

The SSD-507 used to power the shunt field is given 240VAC line input. The needed DC Voltage is adjsuted, then output to the shunt field of the motor (F1/F2) using what would have been the armature (A1/A2) output of the 507.

Both the 514C and 507 drives have a full-wave-bridges for field power included. These were not used on either drive.

Eurotherm/Parker SSD 514C and SSD 507 are available online as NOS, used, or new. I found pricing to be about $375 for a new-old-stock 514C and about $75 for an excellent condition used 507. Europe/UK seems to have an abundant supply of NOS and used 514Cs and shipping is quick and no more expensive than anything purchased in the USA.

The SSD 514C and SSD 507 are analog, not digital, so are simple to wire and set up. Once power is supplied (fused with semiconductor type fuses), there is simple control wiring and armature
and field power output connections and control switches and potentiometers settings. The manuals are fairly easy to follow (I think I have read it a dozen times) and provide details for the required set up procedures.

I am also using a big-ass 25 mH Hammond choke on the armature power output to smooth out the imperfectly flat DC waveform of the SSD’s thyratrons. With that choke, or 'ripple filter', the motor drive is silky smooth throughout the speed range.

I have to thank Bill for all his time and help and input through this whole process and response to my many questions. There is absolutely no way I could have gotten this far without his input on how implement it. The time he spent on the keyboard and on the phone was invaluable in me obtaining a running, functioning drive.

Just a short time ago, I had no idea what a 4Q SSD drive was. Now I make chips with one!

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everettengr

New member
Personalizing the Controls

Assuming he ever moves off the 'test bench', Bill wants all his controls 'on the apron'. The wiring, control location, and how they are setup to operate was a different personal choice for me.There are many different ways to accomplish the same thing and I will likely tweak things in the future.

I am using the original primary DISC switch on the front of the 10EE to provide overall power or not. When on : the blower operates, the green switch illuminates (visual power on), my digital tach powers on, the back gear interlock solenoid gets power, and both the SSD 514C and SSD 507 get power.

Everything is fused with semiconductor type fuses.

I brought in a neutral line and have both 240VAC and 120VAC provided from a 30A disconnect within reach of the lathe.

I am currently using the coolant pump switch to ENABLE the 514C and find that I generally leave this on all the time. My emergency off switches are wired in series with this ENABLE circuit. The ENABLE circuit allows the 514C to function.

To actually operate the motor, the RUN circuit of both the 514C and 507 are switched. I am using the ELSR lever DPDT switch to accomplish this. This is just a simple NO/NC micro-switch that turns on both DC drives. This allows normal on-off use of the lathe by initiating motor drive and keeps the original OEM on/off functioning. The spindle lock switch is wired in series with the 514C RUN switch, preventing motor RUN if the spindle is locked.

When ready to make chips, I just switch on primary power at the lathe DISC switch, then use the RUN switch at the ELSR lever to power the lathe on/off for normal use.

Speed is controlled by two speed set-point 10K ohm pots. One pot for the SSD 514C and one pot for the SSD 507. The 514C pot is the 4Q control. A single potentiometer provides speed control for both the forward and reverse direction and braking. One-half the travel is for speed/braking in the forward direction, the other half for the reverse direction. Centered is off/braked.

On the SSD 514C drive itself, control pots P1 and P2 adjust the ramp-up and ramp-down (brake) rates. I currently have them set at about 80% maximum and get good ramp up without over-shoot and good braking. It is easy to control speed from zero RPM up to maximum in either forward or reverse, 3000 RPM max with my Kinamatic.

With the 514C at maximum base speed (forward or reverse) the second 507 speed set-point pot is used to control excitation of the shunt field to manage field weakening to obtain 3000 RPM.

Two pots may not seem ideal for full range speed control, but actually function great in use. There are plans to integrate the two controllers with a single speed set-point pot in the future. To make best use of this, the already-mounted tachogenerator will need to be integrated with other changes that slave one SSD drive to the other for a Field Regulator’ function that insures better load regulation when running in the Field Weakened range.

More on the tachogenerator when we have done the research and testing.

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everettengr

New member
What I'd like to improve

The fact that the single set-point pot provides both speed and the braking and stop commands is somewhat of a dilemma. If the lathe is switched off with my ELSR lever RUN circuit, the spindle coasts to a stop without any braking function at all. To brake 4Q dynamically, RUN must be switched on, and the speed set-point pot used to 'call for' braking.

As with may others, I use a lathe in the run-cut-off-measure, run-cut-off-measure mode and prefer to return to the set speed by just moving the RUN lever on-off.

I have been working on a few options to provide braking with only the RUN circuit by using another NO/NC switch in the ELSR tailstock which fires a single-shot timed relay when the RUN circuit is switched off. This briefly turns the SSD back on again, and causes it to command zero speed - like a 'reset' - before ramping back up to the set point- then switches it off before the ramp-up begins. Not a technique actually "in the the book", but this has been tested and seems to work very well as to providing very rapid braking. I will post more details as I finalize it.

While the motor was out of the lathe for bearings and cleanup, I also installed a Tachogenerator on the tail end of it. It is a 50V/1000-RPM unit, has been tested, but is not currently in use. For the time being,
IR” or armature voltage sensing is still being used for feedback control.

The future goal is to use the tacho and combine the 514C/507 units together with a single speed set-point control pot able to cover the entire motor speed range. Tachometer feedback is seen as the holy-grail of DC Drive control. It claims to be able to provide load/speed regulation to within 0.10%. More usefully, it extends the range of RPM over which good stable control applies to 100:1.

We will be happy with even one-tenth of that - 1% - if we can get there. Maybe even less. An extended stable range alone should be an improvement over essentially all 10EE factory drives prior to their own "Monarch Sidney" solid-state DC drive.

Much of this set-up and test is beyond my resources with only one lathe and one motor. I will continue to work with Bill and his 'many motor, many DC Drive' experimental test bench to implement it. Meanwhile, I can make the chips he does not bother to make!

Mark


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everettengr

New member
More Photos

More images of the tacho and the pickup for my digital tach which provides RPM in both forward and reverse.

The scope traces for the 514C show the ramp up from zero RPM to base speed and then ramp down. The spike during initial ramp up is the 507 kicking in and slowing down ramp-up as the field strengthens. The second scope image is a zoomed section of the DC waveform feeding the armature. Both from the 514C.



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Much of this set-up and test is beyond my resources with only one lathe and one motor. I will continue to work with Bill and his 'many motor, many DC Drive' experimental test bench to implement it. Meanwhile, I can make the chips he does not bother to make!

Mark
Fair enough on the chips.

At least I don't have to dig Bronze chips outta the Lady Wife's carpet.. (or navel!)

:)

I have to credit Mark with dragging me out of the doldrums and back to the 'bench' after minding a dying Mum, then standing estate executor duty over a longish period. He topped that trick with finding a means of rapid braking for a 4Q SSD drive that was NOT in the manual. "That was not the school solution. It is NOW" class of discovery.

We were not sure how well this would work. I made a grievous error in advising him he needed an SSD 514C-16, as I use for 3 HP motors, large frame AND small.

His FIVE HP motor, 18 or 19 FLA, really should have had the larger SSD 514C-32 (32 A).

Two things made the less-costly 'undersized' 16A drive work, and ultimately work very well:

- Strapping the 514C-16's optional '150% (of 16A) for 60 seconds' option always true.
It is, after all, rated for SIX HP, thermally, just not at the lower voltage & higher amperage we needed. Still, an erg is an erg, max 'wasted' is but 55 Watts, and it seems to thrive on all that for the length of a heavy cut a lathe with only 20" c-to-c ever encounters.

- the other was actually USING the heavy 'ripple filter' choke, a 25 mH Hammond, that SSD recommends somewhere in the "fine print".

Lots of SSD drives out there in 10EE land. Fewer than 100% that use a full-isolation transformer, not auto-transformer, and also boosted above the minimum (to 332 VAC for this one, 349 VAC for my own ones).

Further, AFAIK, we two are the only ones also making actual use of the ripple filter and the marked benefit it adds to both smoothing, reducing stress and noise, and supporting lower, but still-useful direct-drive RPM.

Widely used and well-documented trick for 'quiet' elevators, nothing at all newly invented - just researching of what had once been seen as 'best current practice', but forgotten decades ago in OUR edge-case of DC motors.

More to come as we sort using the tachogenerator to let the 507 field supply duplicate the functionality of SSD's older 5401 Analog "Field controller" to improve stability when in the Field Weakened range so important to most 10EE.
 
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johninwi

New member
Going to share my ignorance..

Why the use of a 4 quadrant drive, since there is really no negative load on the drive. I had to read up on 4 quadrant motor control, my understanding is forward/reverse with either a positive or negative load, ie. an empty elevator running up (counter wight is heavier) thus the motor becomes a generator and the drive needs to be able to absorb the generated power. Since the loads here are all positive and reverse is a mater of armature polarity could the 512c drive be used? Braking would be a matter of loading resistors and maintaining field voltage to make the motor act as a generator?
 
Going to share my ignorance..

Why the use of a 4 quadrant drive, since there is really no negative load on the drive. I had to read up on 4 quadrant motor control, my understanding is forward/reverse with either a positive or negative load, ie. an empty elevator running up (counter wight is heavier) thus the motor becomes a generator and the drive needs to be able to absorb the generated power. Since the loads here are all positive and reverse is a mater of armature polarity could the 512c drive be used? Braking would be a matter of loading resistors and maintaining field voltage to make the motor act as a generator?

Well...

- first of all 10EE's ARE asked to run in reverse now and then. A 4Q drive needs no external 'contactors' to make that happen, hence no arcs, sparks, contact wear, nor large spikes.

- secondly, braking is better, faster, simpler, and cheaper when it can push the energy back up the grid instead of into heating braking resistors, locally. Again with no relays, contactors, contact wear, arcs, sparks or spikes.

- third, there are types of ordinary turning - heavily unbalanced work, for example, that actually benefit from the 4Q control of an over-running load.

- fourth, installation and configuration is easier, safer, and cheaper. Fewer switches, no relays or contactors, no braking resistors, no need to find one or more safe places to house any of that and isolate it from heat, vibration, or operator shock hazard.

- fifth, to make 4Q 'just work' stouter AND more sophisticated components are utilized. Have to be. Result is a more rugged drive better able to protect itself.

Finally - the price of a better and easier to install 4Q 514C is not all that much higher than that of a 1Q 512C, brand-new. There are also far more 514C 4Q in the used market because so many OTHER users made the same 4Q choice years ago.

512C can be made to work.

Peter, in the UK, did a recent one. AFAIK, he is pleased enough with it.

Integrating it with the old DC panel, its contactors and braking resistors wasn't rocket insemination, but it was work those of us using 4Q drives didn't have to engineer, sort components for, run wire - nor even leave any space for..

As with a Beel/Bicl D510 - another 1Q drive - a 512C 1Q does make chips.

I have several 514C, no 512C, and hardly any of my lesser KB-Penta drives that are not ALSO "4Q". Same reason. 'Goodness' is there, even if I don't use all of it, and I don't have to f**kwith 'contactors' nor braking resistors at all to brake faster than they can do anyway.

And reversing? At really low RPM, just for a lark, I can 'rock' a 10EE spindle back and forth with the 514C in well under a full revolution. Might one-day use that to shake paint cans ... just for the Halibut.

Lazy, Iyam.

:)
 

everettengr

New member
^^^ Bill explained it well.

But, to emphasize, the 4Q provides the braking, whether it be forward or reverse, and with the ramp down set to maximum, braking is amazingly quick.
 
^^^ Bill explained it well.

But, to emphasize, the 4Q provides the braking, whether it be forward or reverse, and with the ramp down set to maximum, braking is amazingly quick.

Yep. And we aren't even utilizing the over-ride terminals that bypass the MIN/MAX limits altogether.

:D
 

9100

New member
I generally am a proponent of keeping the original drive, but not for the reasons most people expect. It isn't so much a matter of maintaining originality but because making a replacement cover all the functions requires a lot of knowledge and effort. It usually ends up with something that will make the spindle turn but otherwise is a mess. Modern drives can do a better job, but you have to know what you are doing. There have been several conversions documented here that appear to be really successful, but not many.

It looks like you have done it right and also illustrates how much effort it takes. Another ancillary result of your installation is that you do not have to stand on your head to work on it. The first time I worked on a Modular, I started having serious doubts as to whether at my advanced age I would be able to finish the job, simply because the positions I had to get in hurt too damned much. Then someone came along with a forklift and put the lathe on a couple of heavy duty horses.

I need to try a filter choke on my magamp control. I used capacitors, but they are working very hard and like to fail.

Happy chipmaking.

Bill
 
Modern drives can do a better job, but you have to know what you are doing. There have been several conversions documented here that appear to be really successful, but not many.

It looks like you have done it right and also illustrates how much effort it takes.
Funny thing about that is... at the end of the day Mark and I were basically working directly out of the Eurotherm/Parker-SSD manual.

Where did others do not as well?

Cheaped-out. Took shortcuts. That's about all.

- Thought they could get by with low-boost or NO boost. Or that a buck/boost wired as autotransformer would do when a full-isolation is needed if only to keep the SCR commutation noise on the load side, not the grid - and yer whole house - side.

- Didn't follow the maker's own recommendations for a LARGE choke as ripple-filter for the type of load motor involved.

- Tried to get by for Field power with an ignorant FWB off a 120 VAC line ==> 90 VDC and ugly ripple. Using an SSD 50X 1Q drive's Armature output instead allowed us to dial-in the PROPER Field voltage and current, set safe limits to it right on PCB, and gave us easy use of a low-wattage pot to control Field-Weakening.

- Insisted on integrating with legacy on-10EE controls that no longer suited the new drive's needs (early Beel/BICL) or even safe locations.

Turns out to be a dirt-simple upgrade, and near-as-dammit ALL OF IT right in the downloadable Eurotherm/Parker-SSD manuals.

Another ancillary result of your installation is that you do not have to stand on your head to work on it. The first time I worked on a Modular, I started having serious doubts as to whether at my advanced age I would be able to finish the job, simply because the positions I had to get in hurt too damned much. Then someone came along with a forklift and put the lathe on a couple of heavy duty horses.
It can actually be easier yet on an MG or WiaD casting than it is on a Modular base casting.

MY 'stuff' is coming off the test bench, where it has been 'remoted' 15 or 20 feet to the 10EE when the motor under test is actually in the lathe at all - onto the UNDERSIDE of a $25 aluminium folding-leg step-stool/mini-scaffold.

That will pull-out of the former MG's doghouse on rollers - much as a WiaD's 'works' do.

Difference is that the former "legs" will swing a plate with the two SSD drives with their LED's and trimpots UP to folding-chair or stool seated eye-level for diddling with the trimpots. No bending. No knee-squatting.

No real bending at all once it has been wired, as it gets Hubbell twist locks for each of AC input and DC output so it can be pulled CLEAR out.

Even the controls on my one are slated for RJ-45 jacks and CAT5'S' screened 'patch' cord remoting.

Motor peckerhead has already been shed. A male Hubbell at about 2 O'clock pointing aft will replace it so I don't have to crawl in there and f**k with screw terminals.

I need to try a filter choke on my magamp control. I used capacitors, but they are working very hard and like to fail.

Not sure it will make a positive difference.

Your approach is 'Iron & copper heavy' already, basically sine-wave end to end, even if phase-distorted.

The single-phase SCR's we are taming are seriously rude bastards at abrupt switching anywhere short of full-on loads. Nearly vertical rise, 'remaindered' Sine wave tail-off to zero-cross.

Lower the RPM demand, lower the ON portion of the duty cycle, wiiiiiider the gap between power pulses, and harder it is for the motor ALONE to smoothly integrate the area under the (ugly) 'curve'.

Mind - a 514C has EIGHT trigger coils. Four each direction.

It has only about a quarter of the 'AC component' of a Beel/BICL 1Q one-trigger drive.

Adding the choke makes that very, very close to as smooth as the original MG, but not ....quite.... yet....

Good 3-Phase DC Drives similarly cheat to derive 24 pulse mode rather than the native six.

No real need of ripple filters, but OY! How smooth they could be if so equipped!
May play with one next fall.

I do have a 10 HP RPC, 10 HP Phase-Perfect, and 10 kW 208-Wye capable diesel added to "the lab" now, so a 3-P DC Drive is no longer hard to feed.

:)
 

9100

New member
I made two systems, one single phase and one three phase. The capacitor gives over 300 volts DC from a 240 VAC supply. The motor insulation will take that if you have the DC equally divided between plus and minus ref frame ground. Using only a choke requires a boost transformer since the capacitor charges to near peak voltage and the choke doesn't. The magamps are not the typical design. I wrapped the control windings over the power ones to get close to complete saturation. The cores for the single phase unit cost me over $300. Then I had to wind them and make the rest of the setup. I could have used a couple of toroid cores, but winding heavy wire on toroids is not my idea of entertainment.

Another thing I notice is that Mark understands electronics, which is often not the case when machinists try these conversions. Of course, machinists are not supposed to study electronics. A while back I was asked to trouble shoot the spindle drive on a LeBlond Makino mill. When the customer called tech support, he happened to comment that the spindle encoder was working properly. The tech guy asked how he knew. When he replied that we had checked it with an oscilloscope, tech guy said it was the only time a caller had said that. Machine shops are not supposed to have oscilloscopes.

On a basically choke input filter a little capacity on the input side makes a big difference because it provides a floor for the choke to work against.

Bill
 
I made two systems, one single phase and one three phase. The capacitor gives over 300 volts DC from a 240 VAC supply. The motor insulation will take that if you have the DC equally divided between plus and minus ref frame ground.
I've forgotten if that is on your 10EE - or your Sheldon?

The 'large frame' 3 HP Reliance goes into commutator arc-flash around 330-360 VDC, 'normal' coil connections, carbon-dust dirty, perhaps higher-yet if squeaky-clean.

I run my 'nominal' 230 VDC around 275, 'nominal' 115 VDC Field max set to 140, have ripple-filtering on the Field as well as the armature.

Another thing I notice is that Mark understands electronics, which is often not the case when machinists try these conversions. Of course, machinists are not supposed to study electronics.
Actually.. Mark is a degreed Engineer. Just happens to be an ME degree rather than an EE degree, and didn't initially think he had the electronics. Once you have the maths and can grok a new set of units? Migrating from one field of Engineering to another is not as hard as it might be for others. Well maybe genome/Bioengineering or exotic Organic chemistry, but ME and EE use lots of similar maths, understand resonances & waveforms, so..

Anyway.. he read the manual, asked questions, ended up pushing MY limits as well as his own, and the project JFW. Did buy the Rigol 'scope for the project, but wot they hey - they are useful critters anyway.

Machine shops are not supposed to have oscilloscopes.

CNC'ed shops? That has been changing for 'a while' already. Many do.

I'd not stop with JUST a scope. I'd also want a logic analyzer and a decent Protocol Analyzer - just as I had for International 'Gateway' Telco switches and digital routers, etc.... but then... I don't pay others to fix the 'puters on the Jaguar, either, so..

On a basically choke input filter a little capacity on the input side makes a big difference because it provides a floor for the choke to work against.
Cap input filter is not a good idea on SCR drives. They are 'current' animals first and always, need a zero-cross or near-as-dammit to cut-off, voltage peaking right next door to the bridge array is counterproductive. TWO chokes, caps in between, then again ahead of the Armature? Where have we seen that before?

:)

But even any caps at all are more added failure-points than good sense. The choke & motor do their integrating in the current realm, and they do it rather well. Lot more Iron and copper than one could squeeze into a console radio or a Gates 5 kW AM broadcast transmitter of the 1930's.

BTW ... already scheming a 'Kelvin' lead at former-peckerhead to reduce IR feedback latency.

SSD reads Armature voltage right at the SCR bridge array exit, filters the bejaysus out of it, then feeds it to the same Op Amp/Comparator as the uber-uber smooth UNFILTERED tacho input would speak to.

Tacho feedback increases the useful regulated range from 2% and 10:1 for IR to 0.1% and 100:1 for good tachogenerator.

Ripple filter, Kelvin lead, modest filter just may split the dif for less cost and hassle than trying to squeeze a tacho into the MG base casting space, TS-ward end of the motor. Which dasn't even have an exposed shaft on the 3 HP large frame.

Mark's Modular of course HAD space, even with the longer 5 HP GE KinaMatic. He fabbed an extension to the already-exposed shaft, fabbed standoffs to mount a known-good tachogenerator he picked up used from a nearby CNC repair shop.

It works, too! We just haven't sorted the needfuls for the Field-Weakened range just yet.

I will need the smallest of the Servo-Tek line, and probably bought new. At least they are still US-made!
 

9100

New member
That is on the Monarch. For the Sheldon I have a simple 3 section Variac feeding three of the transformers like the one I sent you to a full wave three phase bridge. That feeds a 15 hp DC motor, primitive but works well. For my South Bend, which now resided in a local motorcycle shop, I made two of the same transformers into saturable reactors by stripping off the secondary windings and keeping the 240 V primary. I put control windings on the outside legs, sort of inside out for normal reactor design. The two are run in open delta and controlled by a single MOSFET. The 5 hp motor formerly ran a locomotive air conditioner compressor. It will slip the flat spindle belt, so that is the elastic limit of the design.

Cap input filter is not a good idea on SCR drives. They are 'current' animals first and always, need a zero-cross or near-as-dammit to cut-off, voltage peaking right next door to the bridge array is counterproductive. TWO chokes, caps in between, then again ahead of the Armature? Where have we seen that before.

Reactors don't have that problem. They supply whatever current they are set up for and that is that. One of the things I especially like is that the starting surge is limited to the rated max running current, much easier on the commutator. Just for grins, I have started the 10EE with the spindle locked. It draws rated current, no more. I can't leave it that way long because all the current is going through one armature winding instead of being distributed between all, but nothing blows up. The current limitation does not depend on a safety circuit functioning but is built in, intrinsic to the design.

Re engineering, my personal observation has been that a person needs a certain amount of intelligence for life support and housekeeping and from there on the ability to understand electronics, like the ability to make money, resides in a separate lobe of the brain, as Alistair Cooke pointed out. Those who have it can understand circuitry easily; those without it can never see how some people do it. Schooling helps get all the ducks in line but no amount can help some.

Bill
 
One of the things I especially like is that the starting surge is limited to the rated max running current, much easier on the commutator.

True as far as it goes, but it was, after all, a Reliance Electric & Engineering "white paper" that pointed out - from testing - that a good DC motor could stand as much as six to NINE times its nominal rating for 60 to 90 seconds before 'wedging' commutator bars or melting a winding.

All the 514C-16 can deliver is 150% of is nominal 16A max, and that for but 60 seconds. That 24 A is just twice the nominal 12 FLA of the 3 HP 'large frame' Reliance, time-limited, as well, so no real risk.

I've no need to use that for accel, but it surely does make braking and reversing much faster on the 3 HP, and was the primo contributor to allowing Mark to get by on a 18 FLA motor with only a nominal 16A drive. He has essentially ZERO risk of over-cooking his 5 HP KinaMatic, so we are both well-pleased with the work of the SSD folks.

:)
 

everettengr

New member
Another thing I notice is that Mark understands electronics,
Bill

Well..., I understand enough to generally think I know more than I actually do, but try to realize my limitations. But, like Bill said, "the project JFW". And, while it was a lot of work, I learned a lot and hope this helps anyone else struggling with their tube drive and considering retrofit drive options.
 








 
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