Help understanding IEC motor diagram

[Electromatic]

Could anyone help me understand the motor diagram below? It is from a cooling fan inside an AB Powerflex drive.

It is a single-phase motor with a capacitor. I believe the symbol under U1 is the thermal cutout. The large, black rectangles are the start and run coils? Is the symbol between N and Z the capacitor? If so, why is it external? Or is Z a speed control wire from the drive?
TIA

 

[eric stromberg]

Looks to me that the bottom rectangle is the run winding. The top rectangle is the start winding. The contact is the centrifugal switch. Once the motor has started, the contacts open and the start winding is taken out of the circuit. This seems to be the case, but, if it is, there seems to be a start capacitor that is missing in the circuit.

 

[Electromatic]

I think IEC uses two straight lines for a capacitor instead of straight and curved, so it ends up looking like a N.O. contact. I don't understand why it is shown external to the motor unless wire Z is some kind of control wire--PWM to the start winding??

 

[Jraef]

It’s show external because it is. That’s done when the motor is needed to be very small and/or inside of something else.

 

[TwoBlocked]

I'd say there is an external capacitor for the, so called, "start" winding. Only there is no centrifugal switch. It is energized all the time. Not as efficient, but for a small cooling motor, why bother with a centrifugal switch? Usually a set up like this just has the "start" winding with finer wire to create the needed phase shift.

 

[Electromatic]

Could the external capacitor and the Z wire be used for speed control? Just curious.

 

[Julius Right]

All the letter is a connection terminal:
U1-U2 Primary winding
U1-Z Secondary winding
L supply live
N neutral

 

[kwired]

Could the external capacitor and the Z wire be used for speed control? Just curious.

Not really. Since this application is a cooling fan there is likely no need to change rotation direction, but there are things like linear actuator motors that have similar electrical concept to them and you reverse rotation by swapping the two motor leads that are connected across the capacitor.

 

[Jraef]

By chance is this for a larger PowerFlex 700H drive?

 

[Electromatic]

It is for a Powerflex 700 drive. With much difficulty, I think I've found a replacement fan. I was also just curious about the wiring diagram and the 3rd wire.

 

[Jraef]

That 700H was an anomaly, because at the time, Rockwell had not completed their large drive development, so they used the power structure from Vacon. The Vacon drives used a weird scheme for powering the heat sink cooling fans that used 3 phase fan motors that were powered from single phase and de-rated to 1/3 of the motor torque. They used a weird capacitor arrangement to get them to start spinning. I think that’s what might be seen here. These things had a high failure rate and Rockwell provided, for a while, a retrofit kit that replaced it. I’m not sure if that kit is still available as they have not sold 700H drives for a decade or more.

 

[Electromatic]

It's actually turned out to be a pain to get a replacement.
I found one where the model # and all the specs matched. However, it was a 3rd party seller on Amazon. That is now tied up in DHL's delivery system, and only the seller can modify the ship-to information.
I'm waiting on another one from a different source. The last two digits of the model don't match, but I found a description somewhere that says that means the fan leads don't come pre-terminated to a pin connector. So...I think I also found the correct pin connector to attach to the drive. (I'll splice the old one back on if I have to and everything else matches.)
I reached out to the fan manufacturer. Because this model was proprietary to Rockwell, they couldn't give any information about it whatsoever--including a possible replacement model number. Freakin' Rockwell!!!!

 

[LarryFine]

Freakin' Rockwell!!!!

Isn't that a company on The Flintstones?