Miele vac motor diagnosis

[Cascadel]

My Miele Callisto canister vac motor doesn’t turn on when the switch is turned on. I checked voltage in each of the 3 wires that plug directly into the motor housing receptacle. When the switch is turned on I am measuring 120v at each of those 3 wires but the motor doesn't run. When I bypass the motor’s triac in a bench test it does run. The triac however tests good with a reading of 070 across legs 1 and 3, and 1 across legs 1&2, and 2&3. I'm stumped, what is left to test?

 

[jj4091]

If you were checking live to earth is the neutral OK?

 

[Cascadel]

One probe of my multimeter was connected to one of the 3 motor supply wires and the other meter probe was connected to the ground wire of a plugged in 3-way extension cord. I used this setup because I wasn't sure which wire was the neutral. I was very surprised to find all 3 reading 120v. Note - the 3 wires were not plugged into the motor when this test was performed. There was no 4th wire neutral.

 

[Cascadel]

Ok, I figured out which is the neutral wire. I'm not seeing any current flow from black or red feed wire when connected to neutral wire. I tested the reel feed and neutral and am getting 120v across them. I'm assuming therefore the circuit board has a short in it. Sound reasonable?

 

[JohnD]

It's worth mentioning that you are in a country where 120V is the supply voltage, hence the test figures.

I don't think we have that model here, it looks rather like a C2 apart from the different voltage.

 

[Cascadel]

Any guesses as to why I am seeing 120v on the neutral vac wire (that would plug into the motor) when my multimeter is attached to my extension cord's ground wire (for test purposes) but 0 volts when I connect the meter to the vac's hot wire (that would plug into the motor) and the same neutral? Where is that 120v coming from?

 

[jj4091]

Not being able to see your appliance or a circuit diagram I guess that you are reading 120v that has passed through one of the coils to your meter to earth and the the problem is a broken neutral wire in the supply cable. Do a continuity test on all cores of the cable.

 

[Cascadel]

Thanks for the helpful continuity test suggestion. I discovered the neutral wire feeding into the cord reel has no continuity with its blade at the plug end. Since that neutral wire was showing a voltage of 120v where it plugs into the motor I'm going to assume it shorted across the hot supply wire inside the reel. Hoping I'm right I've ordered a replacement cord reel.

 

[JohnD]

In that case, the connection in the plug is the first thing I would suspect. Can you cut the plug off and connect a new one?

 

[Cascadel]

Since this cord reel was recently purchased used on eBay with a money back guarantee I'd rather just send it back and try another one.