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Phase A Matic quit

Fred V

Plastic
Joined
Feb 14, 2012
Location
pensacola, fl.
I have a switch that cut out the start capacitor once my idler motor spins up. Yesterday I forgot to throw that switch and then I smelled smoke. This is what it look like inside.
phase a matic.jpg
The capacitor has leaked a small amount of tar and seems to take a charge from my digital volt meter. The burnt wire above the green resistor is the red wire to the capacitor. The blue wire below the resistor is the other wore from the cap. Both are still solid wires.

I think the cap. is a start cap. and it failed. Is that correct?
Fred V
 
That's what usually happens when a start cap is left in-circuit. However, I've not seen a 'Phase A Matic' that didn't have automatic switching. Is this a home-brew unit that you're just calling a Phase A Matic?
 
I must admit I've never seen a Phase a Matic with a capacitor cutout switch either. As a matter of fact I haven't seen any commercially built phase converter that doesn't have an automatic cutout. Maybe some better pictures would further define the make and model.
 
That's a static unit. You can combine it with a motor to make an RPC (factory blurb explains that), and IIRC you DO need to open a switch from the RPC idler to the static box after starting. It's in the generated leg, I believe.

The capacitor would likely need replacing if it leaked anything, and the relays and resistor need checked out
 
That's a static unit. You can combine it with a motor to make an RPC (factory blurb explains that), and IIRC you DO need to open a switch from the RPC idler to the static box after starting. It's in the generated leg, I believe.

The capacitor would likely need replacing if it leaked anything, and the relays and resistor need checked out

Yes, I'm using the P A M to start a 3 phase idler motor. The wiring instructions say to add a SPST switch to the B terminal output wire to open that circuit after the idler motor revs up. I guess that left the start capacitor in the circuit.

I removed the cap and replaced it with another one but it still won't start the idler motor. The shaft turns slowly and won't rev up.

I tested both cap's with a volt meter on ohms. The reading went up to and point and stopped. Is that a worthwhile test?

Can I test the relay? what is the square black box about 2" square?
Fred V
 
The reason for the switch is to prevent problems from the box switching back to the start-up mode (presumably due to voltage drops). The general application blurb for a typical PAM unit is linked below.

https://phaseconverters.phase-a-matic.com/Asset/SIS.pdf

Did you replace the capacitor with another one of the same value? Those are rated in ranges, like 108-134 microfarads. The size capacitor depends on the motor power range the box is for. The wrong size may not work well or at all.

For what it is, the P.A.M. is not bad, it has the same parts that are in other devices made to start 3 phase motors from single phase. Even many RPC units have similar or same parts etc.

As for that one, the relays are pretty tough, but the resistor looks like it got pretty hot. Make sure the resistor is the value it should be, although the marking of value may have been cooked off of it. Usually if it retains resistance, that type is still at or close to the original value. I'd suspect something around 15k ohms is the original value.

The PAM circuit is similar to the circuits shown in the sticky above, so you can look at them for one with the same parts and wiring. It will not generally have the "run capacitor" that most RPCs have.
 
Thanks for your input. The spare cap. is 378-454 mfd. The original was 270-324 mfd.

New info. I rope started the idler motor and checked to see that I have all 3 wires powered to the mill. I am not able to start the mill spindle. The motor starter relays will not energize. I can manually push the relay in and the spindle motor runs. None of the other motors will run off their buttons. Any ideas about that?
 
All I can tell you there is to check the voltage to the relay coils, and check that the coils have reasonable resistances (not super high, not very low). You can take them out and check them by themselves if you keep good notes on connections.

You pretty much have to identify the things that need to work, and check them out one by one. Yes, it is a bit of a "slog", but there is no help for it as far as repairs.

At a certain point, it becomes economical to simply replace the static converter and move on with life. Or convert to a pony start, etc, etc.

There are, I believe, conversions out there on the 'net" which show automatic disconnects for replacing that switch.

BTW, too much capacitance can be as bad as too little. While your substitution is not extreme, it is best to get the closest possible value in order to really check the operation without having other issues added to the original problem.
 
Thanks JST. FYI I emailed P_A_M that I had left the switch in the on position and asked what damage was done and got this reply:

"Because the switch was on went the idle motor was running, the idle motor was back feed energy to the static phase converter

Therefore the wire got hot and melt the wire insulation also damage the capacitor, the resistor, and most important the relay

All those components are damage and need to be replaced. Or you can by a new static phase converter."


I can get another brand for about 100 bucks so I'll do that.
Fred V
 
I have a switch that cut out the start capacitor once my idler motor spins up. Yesterday I forgot to throw that switch and then I smelled smoke. This is what it look like inside.
View attachment 316221
The capacitor has leaked a small amount of tar and seems to take a charge from my digital volt meter. The burnt wire above the green resistor is the red wire to the capacitor. The blue wire below the resistor is the other wore from the cap. Both are still solid wires.

I think the cap. is a start cap. and it failed. Is that correct?
Fred V

so lets do a parts cheek you have two Relays 1-Potential and 1-4 poll double throw . two resistors 1-5 watt wire wound and a 1/4 watt .one neon pilot light and one start cap its no big deal it just automatically dose the same thing that using a start cap by itself dose as far as what could be bad first off we know the start cap is toast next the contacts on the 4 poll relay may be burnt Potential relay mite need to be changed but depending were you buy your parts for 50 to 75 you can replace the cap the two relays and the two resistors i have made them from my junk parts for Nada

013.jpg
 
Don't buy Phase-a-Matic again. Build yourself something better.

These Phase-a-Matic units are such flaming turds.
I can't believe the moderators don't ban discussion
of them like they do those Hanyung VFDs.
They are parts thrown in a tin can box and sheet
metal pointy screws holding everything together.
They must sell a million of them, because they
are like $65 or something. But they are frustratingly
cheap. Probably like Hanyung VFDs and Atlas lathes.

-Doozer
 








 
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