Sciencemadness Discussion Board

Wiring Vacuum Pump

bfesser - 16-7-2011 at 09:26

I just picked up an unused ULVAC G-10DA(S) pump from a local surplus shop. It has a Panasonic motor labeled M91C60S4DU1 with four leads; 1 black, 2 grey, 1 white. The box also had a JSU23X126AQC 230VAC 12μF capacitor inside.

I think it's a single phase motor . . . but I have no idea how to properly wire it. I'm not clueless with electronics, but have little to no experience with motors. What goes where? The paperwork that came with it is poorly translated and says nothing about the motor itself. My Google search attempts have likewise been fruitless. Any help would be greatly appreciated.

[Edited on 7/21/13 by bfesser]

watson.fawkes - 16-7-2011 at 18:18

Quote: Originally posted by bfesser  
It has a Panasonic motor labeled M91C60S4DU1 with four leads; 1 black, 2 grey, 1 white. The box also had a JSU23X126AQC 230VAC 12μF inside.
My first guess is that it has separate start and run windings (look up these terms). The capacitor is there to deal with a single-phase supply (it creates a phase shift). If the start windings are rated for continuous duty, you can just use a single power switch. Otherwise you'll need a momentary start switch as well. It seems like that model says "capacitor run", which means that the capacitor is in the circuit after the motor starts up.

First thing to do, though, is to get out an ohmmeter and figure out what's connected to what.

bfesser - 19-7-2011 at 15:17

Black-Grey 1 = 26.0 Ω
Black-Grey 2 = 25.8 Ω
Black-White = 16.0 Ω
Grey 1-Grey 2 = 0.1 Ω
White-Grey 1 = 10.0 Ω
White-Grey 2 = 10.2 Ω

Black-Grey = 26 Ω
Black-White = 16 Ω
White-Grey = 10 Ω
Grey-Grey = .1 Ω

I've read that it's a single phase 4 pole capacitor run motor.

I've found this...
but it has no info for wiring one with two grey leads.

watson.fawkes - 20-7-2011 at 07:48

I have to say that I'm a little puzzled about all this. Something's missing, maybe a part, maybe some information. You may want to read the following page on internal motor circuits:

For the two grey leads, does one of them have a marking stripe spiral around it? It find it a little odd that they're not distinguished in some way.

I looked up the capacitor. The designator JSU23X12* looks like a UL code for a 230 V rated 12 μF capacitor. What I can't tell is whether it's a metallized-film capacitor, which is rated as a run capacitor, as opposed to a back-to-back electrolytic type, which are only rated for start service. Can you tell from the case type (or other indicator) what type it is?

Given the resistances and the color code, it's pretty clear that the black-white resistance is one of the two run windings and that these two go to the main in the ordinary way: black=hot, white=neutral. My best guess is that the white-grey1 resistance is the other run winding. So in a standard capacitor-run motor, you'd put the run capacitor across black-grey1.

What's missing is what the grey2 terminal is for. My best guess is that it's for a start capacitor, that your motor requires two capacitors ordinarily, and that you're missing one of them. Under this hypothesis, the motor has an internal centrifugal switch. You could check this out in one of two ways. (1) Take apart the motor and look for the centrifugal switch. This isn't as difficult as it sounds. I take apart fractional horsepower motors to lubricate them fairly often. (2) Spin up the motor, probably by using another motor, and see if the resistance changes. Given that the motor would be acting as a generator, you don't use an ohmmeter for this. If it's wired like I think, then the grey1-grey2 connection should open up when the motor is up to speed.

bfesser - 20-7-2011 at 15:54

Unfortunately the motor appears to be sealed--probably designed to require no maintenance. Also, I'm guessing that it's the run capacitor. The motor shaft is a bit strange . . . it'll take some ingenuity to connect the shaft to anything but the pump.

bfesser - 23-7-2011 at 13:25

I tried black to hot, white to neutral, and the capacitor bridging black to grey, and it seems to start and run just fine (just ignoring the second grey lead entirely). The problem is, it's turning counter to the way I need for the pump to run. So, to reverse it...?

I hope I never have to deal with surplus Korean induction motors again! This is making me appreciate the simplicity of aspirators more than ever before.

unionised - 24-7-2011 at 01:42

Try connecting the capacitor to the other grey lead instead.

bfesser - 24-7-2011 at 04:32

It starts in the same direction.

weldit - 24-7-2011 at 05:21

If it is running backwards switch the leads. Also all 4 wires need to be connected for it to run properly.

bfesser - 24-7-2011 at 05:54

Switch which leads? Black and white?

watson.fawkes - 24-7-2011 at 06:53

Quote: Originally posted by bfesser  
The problem is, it's turning counter to the way I need for the pump to run. So, to reverse it...?
This bolsters the hypothesis that you're missing a start capacitor. Capacitors induce phase shift. The phase shift between the two coil windings determines how the forces are timed within the motor. As a rule, with a capacitor-run motor, the forces during operation are agnostic as to rotation at the operational speed. Therefore, some extra capacitance, introduced only while the motor is spinning up, breaks that symmetry and induces one direction or another.

You can test this by mechanically spinning the motor shaft before turning on power. If this hypothesis is right about your motor it should continue to operate in its initial direction. You can use a strap-and-handle to spin up the axle initially, just like a toy top.

With a three-phase motor, you switch the direction of the motor by swapping power leads, which inverts the phase relationship within the motor. Since the phases are at 120° with respect to each other, you don't have the same symmetry as with single phase motors. This is the reason that 3-phase power is normal for industrial electric motors. You have none of these start and run issues and no extra capacitors or centrifugal switches to fail.

arsphenamine - 24-7-2011 at 07:49

NB, Motor run caps are always film not electrolytic since the latter has excessive dielectric loss that would lead to heating and explosion from the heavy current surges in motor start/run usage.

They are usually built from metal foil (not film), polypropylene film, and a refined mineral or ester oil to promote self-healing if used beyond their ratings. Excessive burn-through and healing measurably increases the unit's dielectric absorption and heating.

bfesser - 25-7-2011 at 09:50

I tried connecting the 12µF capacitor between neutral and one of the grey leads (still with black to hot and white to neutral). If given a little nudge, it starts in the desired direction and continues to run. For now, I've detached the motor from the pump head; but the motor provides enough torque to keep running when I grab the end of the shaft between finger and thumb.

So, it does seem like I have the run capacitor and need a start capacitor. What capacitance would be necessary?

Also, does anyone know of any free circuit diagram software that they would recommend? It would be nice to be able to post my diagrams for this thread.

[Edited on 7/25/11 by bfesser]

watson.fawkes - 25-7-2011 at 10:37

Quote: Originally posted by bfesser  
So, it does seem like I have the run capacitor and need a start capacitor. What capacitance would be necessary?
Only a guess, but I'd say that it's the same as the one you've already got. If the two grey leads aren't distinguished, then it may not matter which capacitor goes to which lead.


RLBRADLEY - 28-10-2011 at 16:41

Don't know if you ever got yours running but I have the same pump/motor combo. Mine was used and came with a wired pigtail on it but no run cap.

The two grey wires were already soldered together when I got it so I wired it up HOT (black) to black, neutral (white) to white and the cap between the grey and black and it ran backwards.

I then switched the power HOT (black) to the grey lead, Cap in the same position between the black and grey, neutral (white) stayed connectrd to white and it started and ran great....I used a 15 uf 440volt motor run cap because that was what I had on hand....pulled down to below 50 microns on my Micron gauge...sweet little pump.

Basicly wired like the Single phase Reversible motor CW diagram at lower left but you have two greys instead of one grey : Here

bfesser - 7-11-2011 at 09:52

I don't have any 15 μF capacitors on hand, but I found three 5 μF capacitors. I wired them in parallel between the black and grey leads of the motor. Then wired white to neutral, and grey to 120 VAC at 60 Hz, as you said. When voltage was applied, the motor instantly kicked on and the pump pulled a vacuum. No running data yet, but I'll test it more when I get a single 15 μF motor run capacitor. Thank you, RLBRADLEY for your advice! Time to scrounge up some vacuum chambers and more components.

RLBRADLEY - 11-11-2011 at 07:54

It should work fine with the 12uF Cap you have if wired as described...the motor is rated on it's rating plate/sticker to use a 12uf cap. at 110-120 volts.

I only used a 15uF as that was what I had on hand, it will run hotter and draw more current with a 15uF VS a 12uF...a 12uF is what is optimum for this motor.