Thread: Rivett 1020S - Video and electrical hum question

Don’t know if this means anything, but measuring the current on each leg going into the machine and out to the motor....

For both into the machine and out to the motor I’m seeing about 6, 9, and 9. At startup on one of the legs I’m seeing a peak of about 49 amps.


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Thermite I believe it was you that advised me in another thread to rewire the transformer for 220/110 as opposed to the 440/220 that it was wired for even though it’s being fed 220. I did that during my testing here just a little bit ago. It seems that after doing so the lathe takes a little longer to start and the electrical “grunt” noise lasts a little longer. I’ll also note that it tripped the 10 amp breaker on the phase converter on the first start after making this change so I moved the plug to a receptacle with a 20 amp breaker which is what it was supposed to be plugged into in the first place.


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RPC: It's definitely big enough to run your lathe and the AMP comes with the proper 'stuff' for hard starting

Reeves Drive Belt: It's loose, but it seems to work. The reeves in the Rivetts are fairly tight

The Hum: If someone missed the control circuit transformer when converting the machine from 440 to 220, it is very likely that they missed the wiring of the reeves drive control motor that gets its power from the windings of the main motor. I do remember that the wiring to that motor changes with the voltage change. I have no idea if that would cause your hum, but it seems plausible to me. You could have a variable/non-complete phase loss that is most prominent on start up. One of the windings is seeing a voltage mismatch on starting? Of course, this assumes that the quick-and-dirty tests that Thermite suggest are negative. I would check your mag starter too.

Another thing to check while you're cleaning up loose ends is the motor brake. The motor brake uses a coil to lift the brake and that coil needs to be changed to the appropriate size when converting from 440 to 220. If they missed the control circuit transformer, then they definitely missed the coil in the brake.

Originally Posted by TravisR100

Don’t know if this means anything, but measuring the current on each leg going into the machine and out to the motor....

For both into the machine and out to the motor I’m seeing about 6, 9, and 9. At startup on one of the legs I’m seeing a peak of about 49 amps.

I'm not familiar with the 1020's motor. D'you have the data off the plate?

I'm presuming your meter has the "hold" function so you are actually capturing the peak, not having to make multiple runs and guess?

Originally Posted by medsar

Another thing to check while you're cleaning up loose ends is the motor brake. The motor brake uses a coil to lift the brake and that coil needs to be changed to the appropriate size when converting from 440 to 220. If they missed the control circuit transformer, then they definitely missed the coil in the brake.

Good catch!

I didn't know it had such a critter, but that clatter CAN BE characteristic to either a Warner or Dings brake seeing a momentary drop as to hold-off. Those I DO have. Most of us have heard it on automotive AC compressor clutches, too. Same tribe, conceptually - different Voltage.

Originally Posted by thermite

Good catch!

I didn't know it had such a critter, but that clatter CAN BE characteristic to either a Warner or Dings brake seeing a momentary drop as to hold-off. Those I DO have. Most of us have heard it on automotive AC compressor clutches, too. Same tribe, conceptually - different Voltage.

I didn’t think about that either. I looked at the brake motor data plate and it does say 222/440. But maybe they missed wiring that up for 220 and that’s the problem. My understanding is that without power the brake is engaged and power is what causes it to disengage. So maybe what I’m hearing is the brake being slow to disengage? It is a Dings brake.


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Here’s a pic of the motor data plate. Sorry it’s hard to read. Difficult to get a good picture. It says...

TYPE V0-J
Volts 220/440
Min RPM 500
Max RPM 3470
PH 3
Code H
Design B
HP 5
LO volt amps 17.5
HIGH volt amps 8.8
Rating 55 C
Serial 2822956



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Originally Posted by thermite

I'm not familiar with the 1020's motor. D'you have the data off the plate?

I'm presuming your meter has the "hold" function so you are actually capturing the peak, not having to make multiple runs and guess?

No, I’m using a cheap RMS meter and taking video of it and looking at the peak. Waiting on a new battery back for my Fluke meter.


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Ok, THAT exercise took a little while. I removed the coolant tank and figured out how to get the cover off of the brake to get access to the coil wiring. There are 6 coils, 3 on each side. The Dings wiring diagrams aren’t the clearest in the world.



Their diagram is showing the wires from both sets of coils sort of overlaid. Hard to explain. Where you see the what they call the “light” wires (they’re actually yellow) labeled 4 and 0 above and the black wires labeled 1 and 7, wire 4 is yellow wire from the bottom coil on one side and wire 0 is the yellow wire on the other coil on the other side of the brake. The wiring diagram makes it look like there are 3 coils with 4 wires each. There are 6 coils with 2 wires each.

At any rate, yes, the brake coils are wired for 220. Whomever rewired it for 220 originally didn’t miss it. I have 5 bundles of 3 wires which is 220. If it was 440 I’d have one bundle of 3 wires and 6 bundles of 2.

The manual from Dings also talks about the air gap. It says the gap should never exceed .100. Mine looks to be about .040 which is right where it should be from what I’m able to tell. There are specs and procedures on a label on the inside of the brake cover. Mine are so badly deteriorated that they’re not readable.

If anyone wants to see video of the brake actuating I’ll take the time to pull that video off the camera.

Here is a pic of one side of the brake.



For anyone trying to make sense of the Dings exploded diagrams in the future, I finally figured out what to turn to adjust the air gap and what to turn to adjust the torque. I adjusted neither. In the image above you see a threaded rod with a spring. Starting at the left you have the tip of the threaded rod, a nut (21), the iron plate, a nut (22), more threaded rod, another nut (9), a washer (8), and a spring (7).

To adjust the air gap you adjust nuts 21 and 22. To adjust the torque you adjust nut 9. There is a matching assembly on the other side of both the rod/nuts and the coils.

Oh, and by the way, the cover is held on with two SHCS’s. When you’re trying to get the cover back on you have to figure out where the two screws go to align the cover. There’s nothing that keys the cover to the brake. I would HIGHLY recommend taking a sharpie or paint and marking a line from the cover to the brake so you know how to orient it. The two cover screws actually screw into the ends of the bolts/threaded rod. They’re drilled and tapped on the ends.



Above... newly drawn alignment mark so I don’t have to mess with alignment next time I take this apart.

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Originally Posted by medsar

RPC: It's definitely big enough to run your lathe and the AMP comes with the proper 'stuff' for hard starting

Reeves Drive Belt: It's loose, but it seems to work. The reeves in the Rivetts are fairly tight

The Hum: If someone missed the control circuit transformer when converting the machine from 440 to 220, it is very likely that they missed the wiring of the reeves drive control motor that gets its power from the windings of the main motor. I do remember that the wiring to that motor changes with the voltage change. I have no idea if that would cause your hum, but it seems plausible to me. You could have a variable/non-complete phase loss that is most prominent on start up. One of the windings is seeing a voltage mismatch on starting? Of course, this assumes that the quick-and-dirty tests that Thermite suggest are negative. I would check your mag starter too.

Another thing to check while you're cleaning up loose ends is the motor brake. The motor brake uses a coil to lift the brake and that coil needs to be changed to the appropriate size when converting from 440 to 220. If they missed the control circuit transformer, then they definitely missed the coil in the brake.

Medsar, you say check the mag starter too. Check it in what way? I did measure the resistance across the contacts while manually holding it closed. Is there something else?


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Originally Posted by thermite

It is not "long term safe", but as you are testing, I'd try bypassing the mag starter functionality by mechanically forcing it active, then doing the power ON/OFF with my external disconnect.

End of the day, so long as it is NOT clattering the contactors, there's scant harm.

Even if.. an RPC is hauled-down hard by a starting load, it is still produces smoother-edged wave-forms than a VFD.

I tried mechanically forcing it active and that didn’t change anything. I could try jumpering the contacts for each phase thereby bypassing the contactor. Think that’s worth a try?


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Originally Posted by TravisR100

I tried mechanically forcing it active and that didn’t change anything. I could try jumpering the contacts for each phase thereby bypassing the contactor. Think that’s worth a try?

Not at this time. You have already found low/no resistance, closed, add now having HELD it closed, plus the obvious that all three legs are live or the motor would just lock, not start, I'd leave it for now.

Where I'd look next is into making sure the electric motor brake was cleanly released.

My ones are on 180 VDC DC motors, but have 120 VAC actuation coils.

Your one is more likely to be 220/240 VAC so it could have been run off 3-Phase, leg to leg, given the presence of a Neutral (to provide 120 VAC) is not assured, even in a utility-mains 3-P environment.

An RPC (nor a Phase-Perfect, nor a VFD) does not provide a "legal" Neutral, either, nor should one use PE (Protective Earth AKA "ground"). Even if it works, it is hot the safe way to proceed.

As with Phase-Perfect's manual, if one NEEDS that - "re=derived" or "local" Neutral, then a Delta (RPC/P-P side) to Wye (load side) full isolation transformer is specified. I have such, but not off any need of 120 V.

So.. next "mystery" to look into is how the electric brake is supplied, whether it is getting what it needs to operate, and whether its control circuit is stable or drops-out durng start of accell/decell loading of the RPC. EG; You have confirmed the starter & contactor actuator coils are not on the "generated" leg, but what of the brake?


BTW: All of these inspections on a newly acquired system are positive ones, ultimately, not time wasted.

I have high confidence this will all come good, "soon, now", and probably with little or no significant spend - at least in money.

The brake is supplied by the exact same 3 phase lines as the drive motor. The three legs for the drive motor run through a conduit from the electrical panel to a junction box mounted to the drive motor. In that junction box lines are tapped off for the drive motor, the three phase brake, and the single phase speed change motor.

Interesting that the Rivett wiring diagrams I’ve looked at show the speed change motor as a 110v motor running from the transformer.

I’m thinking it’s just a large draw on the RPC at startup. It does sound fine once it’s running.

I did confirm that the brake is actually disengaging and it doesn’t seem worn based on the air gap. I took video but haven’t pulled it. The brake disengages immediately on startup and stats disengaged.

I don’t know how a .045 movement disengages the brake.

I also believe I’ve checked pretty much everything at this point for conversion to 220. Drive motor wiring, brake coil wiring, transformer wiring (which was corrected), no wild leg to control circuit, right fuses, right heaters.

I am curious about the 9, 9, 6 amp draw however. Is it typical for the legs to draw different current?

I also determined the start button for the coolant motor doesn’t work. Not sure why. Found out the coolant motor does work when I manually closed that contactor thinking it was the starter contactor.


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Originally Posted by medsar

The Hum: If someone missed the control circuit transformer when converting the machine from 440 to 220, it is very likely that they missed the wiring of the reeves drive control motor that gets its power from the windings of the main motor. I do remember that the wiring to that motor changes with the voltage change. I have no idea if that would cause your hum, but it seems plausible to me. .

You say they might have missed the wiring of the reeves motor. Missed what? From what I can tell that motor just uses two of the 3 legs. It works at any rate however the function of the slow/fast buttons is reversed.


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Originally Posted by TravisR100

Interesting that the Rivett wiring diagrams I’ve looked at show the speed change motor as a 110v motor running from the transformer.

I’m thinking it’s just a large draw on the RPC at startup. It does sound fine once it’s running.

I did confirm that the brake is actually disengaging and it doesn’t seem worn based on the air gap.

I also believe I’ve checked pretty much everything at this point for conversion to 220. Drive motor wiring, brake coil wiring, transformer wiring (which was corrected), no wild leg to control circuit, right fuses, right heaters.

All very sound work! It is a pleasure dealing with thoroughness rather than argument!

I am curious about the 9, 9, 6 amp draw however. Is it typical for the legs to draw different current?

Yes, generally. Part of why an RPC has a rule-of-thumb upper bound of about 91% of "nameplate", even on very large RPC's. The "generated" leg is a CEMF "sharing" or partial transfer via what amounts to a "rotating transformer" - the idler - to imitate an all-in-one motor-plus-AC-generator head. Sort of. Simple creature, it works well and lasts a long time, but does have its losses and inefficiencies, even at primo match and balance.

Try a recording of BOTH Voltage and current, each leg, and - if you have the gear for it - all of the legs at the same time, or at least one pass-through (not really..) and the generated.

Not sure if that is a "normal" spread for your motor and its operating condition - it seems greater than I'd expect. 3-P brake shouldn't draw much, coolant pump not active, speed change is used only "now and then", but still...

Are you sure your reading is the motor ONLY? Or are you measuring at a point - RPC output - where the other loads - none of them on the generated leg - apply as well?

Originally Posted by thermite

All very sound work! It is a pleasure dealing with thoroughness rather than argument!



Yes, generally. Part of why an RPC has a rule-of-thumb upper bound of about 91% of "nameplate", even on very large RPC's. The "generated" leg is a CEMF "sharing" via what amounts to a "rotating transformer" - the idler - to imitate a generator. Sort of...

Try a recording of BOTH Voltage and current, each leg, and - if you have the gear for it - all of the legs at the same time.

Not sure if that is a "normal" spread for your motor and its operating condition - it seems greater than I'd expect. 3-P brake shouldn't draw much, coolant pump not active, speed change is used only "now and then", but still...

Are you sure your reading is the motor ONLY? Or are you measuring at a point - RPC output - where the other loads - none of them on the generated leg - apply as well?

I try to deal in testing and facts when possible.

No, I’m not necessarily reading the motor only. I’m measuring in the electrical cabinet just before the wires enter the conduit out to the junction box that serves the drive motor, control motor, and brake. The control motor only runs when holding the fast or slow buttons so no draw there. The brake coils are drawing whatever they need to hold the brake in a disengaged position. I posted the voltages between legs and to ground in an earlier post as well as currents but I did those measurements at different times and didn’t specify or note which legs corresponded to which voltages and currents. I can go back and measure again.

My apologies for a lot of extra info in these posts. Trying to create a bit of a record for anyone else working on one of these machines in the future. I’ve seen several other threads that touched on voltage conversion on the Rivett but they seemed incomplete or trailed off without conclusion.



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Originally Posted by TravisR100

I say in the video when looking at the front ways that the wear seems like it’s probably less than .001”. Haven’t measured it yet but I can’t catch a finger nail on it. Just barely feel it when running a fingernail over it.


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Bed wear is a hard thing to deal with, and has a big effect on the value, or usefulness of the machine. On lathes with really long carriages, the wear near the chuck has less effect on causing taper on the work piece then lathes with short carriages.
The problem you are likely to have is when the carriage travels close to the spindle nose, and climbs up on the unworn area. The best way to determine the wear problem is to begin cutting metal, most often, simply moving the tool post toward the left, that transition of wear spot can be avoided.

Looking at the drive in action, I see the spring on the variable sheave at the right is so loose it flops, probably why the belt is loose, I would do some clean up on those pulley faces, they shouldn't look like that.

Originally Posted by donie

Bed wear is a hard thing to deal with, and has a big effect on the value, or usefulness of the machine. On lathes with really long carriages, the wear near the chuck has less effect on causing taper on the work piece then lathes with short carriages.
The problem you are likely to have is when the carriage travels close to the spindle nose, and climbs up on the unworn area. The best way to determine the wear problem is to begin cutting metal, most often, simply moving the tool post toward the left, that transition of wear spot can be avoided.

Looking at the drive in action, I see the spring on the variable sheave at the right is so loose it flops, probably why the belt is loose, I would do some clean up on those pulley faces, they shouldn't look like that.

There’s actually almost no wear at all.

Someone else mentioned the pulley faces. They are actually completely smooth. It must just be the way the video captures them. They are as smooth as the ways.


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Originally Posted by TravisR100

My apologies for a lot of extra info in these posts.

Don't apologize. Keep up the good work!

PM has become a gold mine for such records for Old Iron that demands more than the piddly stuff.

Cone faces looking brown are prolly a digital camera light-handling artifact.

LOTS of shots on PM have looked like brown-bess musket or acid-fume rust in a foto and were chrome-bright when the lighting or camera angle was shifted.

That loose spring just mentioned? Reeves belts eat their edges up. Bigtime, given time.

New belt should be just enough wider - doesn't take much with both sheaves pinching it, that could come good with no other effort... so long as .. the hub is not "mud mired" from old lube and fretting-corrosion nano-particles inside and hanging-up or vibrating.

Do some research before taking it apart IF you do that at all. I have three here, no two alike. Different makers, different patents.

As to the wear, I just put a .0005” mitutoyo DTI on the cross slide. Between the V way and the flat way in the front. It is a non-bearing machined surface between the load bearing ways. If I run the carriage from the spindle to 2/3 to the rear of the machine, the indicator shows basically no deviation. Not that I can measure without a tenths indicator. If the needle moved, it’s barely .0001.


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