Help understanding fan motor.

Hi,

Pulled a fan motor from a large (new) assembly some years ago. The best I could do was to take some attached components along with it so I could sort it later.

The start cap and a High Voltage Module are there as well as the line cord. The switching assembly had to be left behind. As it was on the street, I could not do any better than I did.

I am scratching my head on how to wire this and want to use it.

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Seems like a selector wired to connect the Red, yellow or brown to the ac input the HV module has (bottom), and connect the other ac input that is going to the black motor wire to the white wire (top side of the HV module) would make sense.

Supplies full power to the HV and motor start cap.

As noted, the 2 black wires have no ohmic relationship to any of the other wires or the motor frame.

I failed to get a reading of the start winding to the other wires so I have some homework to do before applying any power.

The cap, line cord (marked AC) and HV module are as it was in the machine. The 12KV HV output wires are omitted. Why one AC line went to a black wire (and apparently nowhere else) is a mystery. I will undo the plastic covered crimp connector and see if I tore out another wire that connected to them, but it looks like there were none.

Comments greatly desired

Reply to
Splork
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If you can find the value of the capacitor, generally marked on the side.. value(uF MF mF etc) and voltage, part number.

The value will indicate what type of motor it is, although it appears to be a PSC type )permanent split capacitor) motor, and possibly multi-speed (or dual voltage).

There may be worthwhile info on the motor case.. a tag or diagram-p/n on a label inside the wiring cover if equipped.

It sounds like an open frame blower motor from a furnace or air handler which also included an electrostatic air cleaner.. that's likely what the

12kV is for, definitely not needed to operate the motor (should be removed to prevent any surprise shocks which could result in serious injury). If the appliance was a home comfort apparatus, you might try posting a picture on a HVAC forum.

I would cut away the HV module and try to determine if the (top) white lead, and the (bottom) black lead/AC are the power leads. There should also be a secure earth ground connection to the case for testing and use/operation. Testing should be attempted by a qualified, experienced individual with the capacitor in place as shown.

Without a motor manufacturer's name or part number, you may not find any data regarding the other leads (red, yellow).

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Cheers, 
WB 
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Reply to
Wild_Bill

Thanks for the comments.

The device is long gone (8 years) and I suspect it to be what you think it is. What remains wired is done so by crimped wire connectors (like permanent wire nuts)

I asked for comments because I am lost explaining no ohmic relationship with any of the black leads to anything else and one fed from the line voltage lead. There are no other wires connected to that lead so there is no evident complete circuit possible. One power line wire to that lead exclusively.

Other than that it seems a straightforward tapped motor, though the winding implementation needs to be sorted out.

Making White hot and using the windings to selectively complete the circuit is logical.

3uF is what I might expect for a low start torque air handler. Likely permanent. Not a huge motor. Nicely fit to an air directing shroud.

I would suspect a black lead for frame ground but 2 blacks ?? and one wired hot is a head scratcher. Hence my wail for help.

The HV module will come off. I might find a good way to use it in my application for air scrubbing but that is an afterthought.

There is nary a mark on the motor. Nothing that I could get a response for on the net. No Mfg imprint either

I am not a HVAC guy but I did AV Repair when TVs still had tubes and did a stint designing Motherboards in the early PC Market. Not threatening for me.

Thanks again

Reply to
Splork

One possible reason for neither of the black leads showing any continuity to any other wires could be the appliance was discarded for a reason.. maybe the motor went bad years ago.

A 3uF motor cap would very likely be on a PSC type motor. The wiring scheme for a PSC is similar to a center-tapped transformer.. 2 (nearly) identical windings in series.

wire o--------------o--------------o wire

The center tap is a third wire, and the resistance readings from center to each end would be close to identical, and combined, those readings would equal the end-to-end resistance reading.

No manufacturer would use a black wire for an earth ground wire. Earth ground is nearly always green, although sometimes green/yellow.

The white wire is common to the motor capacitor and the HV module, so I'd expect that to be the neutral of 120VAC (located electrically at the center of the 2 windings). The grey wire likely goes to an end of one of the windings.

I'd suspect that one of the black wires was the hot side of 120VAC. Since there's no continuity, then likely a break in the wire-to-winding connection or an open winding.

PSC motors are frequently thermally protected, so a slim possibility could be a bad (open) thermal protector. Trouble is, it may not be easy to find it.

Those insulated splices may be Buchanan splice-caps.. very common in consumer appliance wiring. They're very reliable when crimped properly with the Buchanan crimper.. and the insulating caps just snap on over the splice. Very consistent results if used conscientiously.

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Cheers, 
WB 
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Reply to
Wild_Bill

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It sure would help if you gve the info on the motor nameplate as well as the manufacturer's name, model, anything???

Reply to
hrhofmann

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No nameplate or any other useful marking. I would have exhausted that before asking for a comment.

Reply to
Splork

The box I pulled this out of looked Brand New. The plastic Fan blade, housing and motor had no dust whatsoever. True that the HV charge might have reduced that accumulation, but this was as new. I pondered the possibilities and also thought that the motor might just be open from the black lead. Good reason to toss it. But the schematic makes no sense. Unless it was incorrectly wired from the factory. The white motor winding just begs for the AC line that connects to the black lead.

I have yet to put it on the bench again to measure the start winding and see what relationships show up.

Will report back what I find.

Thanks much for the chat!

Reply to
Splork

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I wanted that as much as they want ice cubes in Hades. Have a perfect application for this.

Almost mark free motor. Tiny label with obscure part number only.

Reply to
Splork

OK, I looked at it again and took some readings that I did not before. The Black wire mystery is solved. Black in to black out is likely an interrupter of sorts. Thermal protection?? Allows the motor to cut power to everything if it senses trouble.

Zero ohms between them. Don't know how I missed that. If it is intermittently failing (reason for discard), I can bypass it.

The gray wire to the brown is 66 ohms, increasing as we move towards white, so brown is the center tap and the start coil 66 ohms.

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So the Black Wire hot out from the motor goes to the white lead, start/run cap, and HV input. Looks good. The other side of the HV input has the other AC leg and it would connect to the brown wire.

I presume whatever switching device is used, it would bypass (short) the brown to yellow or brown to red or yellow to red or so on, to remove power to those coil segments. Something to ponder when I have a moment.

For hrhofann: Part number on unit is 001-02084-000 Ref # DM-60001 Year 04 H

Zilch on lookup by me. Got an idea?? I would love to see how this was intended to be run.

Thanks guys!

Reply to
Splork

I utilize the potential outcomes and additionally imagined that the engine may just be open from the dark lead. Be that as it may the schematic makes no sense. There is nary an imprint on the engine. Nothing that I could get a reaction for on the net.

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Codejohn
Reply to
Codejohn

I've only seen external leads for the thermal protection device on industrial motors (specifically Oriental Motors gearmotors). The purpose of the external leads is for use where excessive motor heat (overload) could be used to signal/actuate/interrupt other devices on a machine.

So the TP (thermal protection) leads for your motor would be wired in series with the L1 line-in, and one of the motor's power connections. The other connection would be for N neutral.

The 2 identical readings between 3 wires would likely indicate the motor run windings, and there should be ~132 ohms measured across the 2 windings in series (end-to-end). If there aren't 2 nearly identical resistance readings between windings found, then those aren't likely to be the run windings (excluding multi-speed connections). BTW, there are no start windings in a PSC motor, only 2 run windings.

I haven't taken any resistance readings of PSC motor windings in a while, so I can't say if the 66 ohm reading is reasonable.

I don't have any suggestions for the red and yel wires. My focus would be to determine if the motor is useable, not all of it's features.

L1 o-----(switch)-----o(blk)--(TP)--(blk)o------(66R)------(center conn)------(66R)

N o--------------------------------------------------------------------------o------[cap]------o

Ground o---------------------------(motor case)

These would be the typical connections for a PSC motor, and how I would test it, IF I were fairly certain of the run winding connections.

I would have separated the HV supply long ago, since it has no use in powering the motor.

If it can be determined to be in working condition, then the possibility of reversing the rotation may be considered.

FWIW, these motors can usually be found for ~$10 (maybe less) for a new surplus motor with a wiring diagram and a specific RPM, from numerous surplus dealers.

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Cheers, 
WB 
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Reply to
Wild_Bill

Reply to
gary.schlender

What you want are suggestions and helpful tips. Self-referentially, this ng has FAR TOO many "comments".

Reply to
Allodoxaphobia

In 2013.

RL

Reply to
legg

He's either been electrocuted or given up and moved on.

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Paul Hovnanian     mailto:Paul@Hovnanian.com 
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Reply to
Paul Hovnanian P.E.

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