Thread: Static Phase converter

Will a 1-3hp rated (phase-a-matic) static phase converter start my clausing 3/4 hp drill press ?

It should!

I probably have this ass backwards but I thought the converter had to be sized close to the motor HP for relay to sense the current inrush and blast the fake leg with the cap. If the converter is way oversize it won't see the proper current draw to react and start the motor. I know that the Phase-a-matic site warns against over sizing the converter..both from an operational standpoint as well as thinking you will get your full oink out of the application.

I have a Delta Unisaw with a 5 HP three phase motor running through a mag and the static converter powers it flawlessly. I ran a B-port off a static converter for years but that deal was going through a drum switch...it worked perfectly as well.

I have been following this thread and am still not sure exactly what is going on...mysterious 'hums' and 'buzz's' but little hard info as to coil voltage etc.

Stuart

With static phase converters, you should always try to have the motor hp fall within the range of the static converter. The reason for this is, when your motor starts to spin, it starts to generate voltage back from the phantom leg of rotating motor thru the caps. If you have to much mfd's in the circuit, the generated voltage will be low and the potential relay will never take the caps out of the circuit. When this happens, the motor will draw to much current after it is up to speed, causing your motor to smoke or caps to overheat or both.
Thats why phase-a-matic, american rotary, wny supply and some others have a indicator light on the panel. This light will show if you have a proper match for hp and caps. If the light shuts off with a few seconds, you have a correct match between caps and motor.

Thanks for the info, my light on my converter is not going on when I try to start my drill press, The reason for asking ,i certainly don't want to purchase another converter if that's not going to help my problem,
Atomarc, where would I need to get this voltage reading, I have 135-140 v on all 3 lines of the off the converter, the starter has 2 push button resets, on 2 lines, 3rd runs through to the motor, no reset but attached to the starter , I dont have the motor wire as the phantom line, As I check the voltage out out of the converter I'm OK but on the motor side of the starter I get nothing, Called the instructor where I purchased the drill Nausau college he tells me the machine had no problems, and by the condition this seems accurate, where and how do I test to narrow my problem, or should I purchase ,wire the smaller converter,
thank you
Frank

Does the drill press motor humm, when you try to start it? If the drill motor is not humming when you try to start it, would indicate that the phantom phase from the static converter is wired to one side of the coil on the starter... will not work that way.

macplus
I have tried changing the phantom leg to 3 different positions , same thing, the motor's not humming the starter or coil is, any suggestions??
thanks

Well then, make sure that the O/L's are reset, make sure the starter coil is good, if there is a control transformer, make sure the fuse is good.

If the starter coil is humming, that means it's getting power, so it must be on the "real" phase, and the overloads must be OK. What voltage is the coil rated for? What voltage are you trying to run it on? I assume 240V, but is it possible the machine was previously wired for 480V? Is there a control transformer supplying coil voltage? If the Xformer is wired for 480V input and you are feeding it half the voltage, it will only be supplying half the intended voltage to the coil, likely not enough for it to pick up.

Note: If the Xformer is wired for 480V, I would suspect the motor is also, and will need its connections changed before trying to power it.

Dennis

Dennis
That's got to be it, It was wired for 480 and I did change the motor. any idea how the starter is changed, It dose not say inside cover
thanks much
Frank

Its an allen,bradley a/c automatic starter cat # 709tad series k ,coil 120v60cy, 110v50cy a/b 69a86
I tried to post a picture , I am as good with computer,s as i am with this wiring. It will not post for me.

How is the starter powered? Does the cover specify the coil voltage, or is it marked on the coil?

On older 240V equipment it was not unusual to have a line voltage (240V) control circuit, but if the machine was designed to be dual voltage (240/480) there were sufficient reasons not to use 480V to the start switch, so a control transformer was usually added. Once the transformer was part of the deal, there really wasn't any reason not to use an even lower control voltage, 120V was common, and provide multiple taps on the control transformer to easily change the voltage. Trace the control wiring from the starter back to the start switch and see where its power comes from... I'm betting there is a control transformer, and a little fuse block to protect the control circuit. If the starter is the only thing this powers, it won't be very big, maybe the size of an old doorbell transformer. It won't necessarily be in the same enclosure with the magnetic starter, especially if the starter is in its factory supplied case, but it's got to be there somewhere. It should have multiple input taps, and a wiring diagram on it somewhere. On the older ones they typically didn't mark the terminals with the voltage, thy were typically numbered to key to the diagram. A real common arrangement was to have the primary coil wound as two parts, lessee if I can remember this correctly... the two parts were wired in series for high voltage input, and parallel for low voltage input. Someone will correct me if I've got that backwards, I'm sure.

One other thing about changing the voltage of a machine that has a magnetic starter; the size of the overload relay will now be incorrect, since the motor will now draw twice the current when it runs on half the voltage. The O/L relays were designed for the sensing element, which are normally heaters, to be easily replaceable, although maybe no longer easily obtainable if the starter is obsolete.

Dennis

Wow Im sorry to say this seems way over my head, the transformer is mounted atop the switch. and connected to the starter by wire nuts. The numbers on the transformer are 220/440 volts, type11353N, 30 sec volts, osborne transformer.but no wiring diagram ,If I follow I should be able to change the wiring at the transformer. to get it to the 220v needed? But O/L relays wont work anyway? Will the motor start without the starter if wired to the switch then motor? can I eliminate the starter?
Frank

Frank,

Yes, you can operate the drill press with a drum switch if you want...FWD/OFF/REV. Almost a convenient as a pushbutton. I am still thinking your static converter is several sizes too large for your intended application though and that is giving you problems. If you mash the plunger on the mag in by hand, and the converter is functioning properly, your drill press should spring to action...this will be the acid test of converter health.

Stuart

I have tried to hold the plunger's in while trying to start ,and nothing. If that's what you mean. When the converter works my lathe or mill the converter makes a start noise along with a test light flash, I get none of that with the drill press no light no start noise. Does what I have described point to the converter? If possible I would like to leave the machine original but it's not to wise if I cant get it to run.

Frank,

I can understand your desire to keep everything stock...and that is totally doable. If there is a control transformer for the control circuit, which would be the coil on the mag actuated by the ON/OFF switch, it must be wired for the incoming voltage. Typically this would be a 240/480 (primary) volt unit you can jumper to fit your incoming power, which would be 240 volts. This probably supplies a secondary of 120 volts which corresponds to the coil voltage on the mag. This transformer must be wired properly and if using a static converter, must be wired to the two active line legs...L1 and L3 (I think).

That being said, I think your converter is sized improperly, it's too large for your small drill press motor. You can contact Phase-a-matic for conformation. There are converters out the wazoo on eBay that would be the proper size for your application and they are pretty reasonable. Anderson has a complete line of rotary and static converters on eBay and you can actually talk to Mr. Anderson himself if you call with questions. Do you have a friend who is more knowledgeable in electrical matters...I would give him a call and ask for some advice. Keep digging but don't ZAP yourself.

Stuart

FWIW, static converter companies always hint that you will lose aprox 1/3 of your total hp. Which seems logical since you lose 1/3 of your power legs once the converter has done it's thing and the 3 phase motor is coasting on single phase power. But the reality is you end up losing over 1/2 of your total HP. Which, on some machines is still enough...but on many, isn't.

Thank you all very much, Ill let you know how I make out, If I don't cut it up for scrap.
Thank you again
Frank

I think the OP has two problems... determining if the machine will run at all, and determining if it will run on the existing static converter.

I think we've already determined that it was previously a 480V machine, and while it has a dual voltage motor, the control transformer needs to be re-connected, and the starter will need new "heaters". The Allen Bradly 700 series starters are long obsolete, but it looks like parts and heaters can be had from Southland Electric, possibly other places.

700 Series Allen Bradley Low Voltage Starters & Contactors -Southland Electrical Supply

The second problem is he doesn't even know if it will run... manually pushing the starter contacts closed should make it start (assuming there ARE contacts in the starter, better check, they are replaceable and could have been cannibalized to keep another machine running) but we can't tell in the motor is n/g, or if it just won't trigger the static converter. It would be nice to know before any further time or $$$ is wasted.

I'm almost afraid to suggest this, since the OP doesn't seem too comfortable around things that spark in the night, but since he has another machine that starts and runs on a static converter, the motor on that machine could be used as a makeshift rotary phase converter to see if this motor at least runs. Basically what I am suggesting is to wire the machine in question (this is a drill press, right?) to the LOAD side of the starter on the other machine that runs (which I thought I read was a lathe, but now can't find it). Once the wires are safely connected, start the motor on the lathe. When it is running, idling, manually engage the drill press starter contacts and see if the motor starts. It may drop the overload relay on the lathe, and if it does it without actually starting means the motor has a problem. More likely, with no load on either motor, it should just start and run. If so, then you can address the other problems, probably most easily by just buying a small VFD to run the drill press, and trash the existing starter.

WARNING: when wiring the two machines together BE SURE to also connect a ground wire between them. Bad insulation in the drill press could allow that machine frame to become hot, and touching the frame of both machines could make YOU the ground conductor, not good.

Dennis

Just an update,, A 1-3 hp converter will run a 3/4 hp clausing drill press, The transformer was wired for 440 and had no wiring diagram on or around, had to purchase a new one from Grangers for the diagram, Then shamefully returned unused, Runs fine now.. thanks to all that helped
Next any suggestions how to design a work holding system on the smooth table ,
Again thanks