Hotwire vacuum cleaner brush motor? Motor only runs for 6 seconds.

[DejaVue]

A common Hoover WindTunnel "Air Steerable" upright vacuum cleaner. UH72405 and similar models. A common problem on them is the brush motor will only run for 6 seconds. They have a button on the handle to turn the brush motor on and off. Press it, brush turns on for 6 seconds, then shuts off. The main motor for the vacuum works fine.

Any idea if I can hotwire the brush motor so it runs all the time? Or figure out which part of the circuit board to replace.

The original brush motor was shockingly rusty on the outside. Bought a new replacement motor to try. Same 6-second problem. An internet search will bring up many people asking for a fix and nobody has a fix.

The problem isn't something wrapped around the brush roller because it does it even with the brush roller belt disconnected. And it's not the lever/switch that keeps the brush motor off when the handle is fully upright. One plug on the circuit board is for the brush motor power. The other is for that brush motor "upright" switch/lever.

 

[Creekside]

My vote would be 2 Wago connectors and to remove the board. The motor is 120v so I'm not sure what the board does unless maybe it's a speed control or something.

 

[brianl703]

The motor is 120V DC so the board at a minimum rectifies the AC to DC (but clearly does more than that). I suppose you could just replace it with a bridge rectifier.

EDIT: The board looks like it might be a speed control for the motor.

 

[Jetronic]

I bet it monitors current, and too much current indicates a stuck brush. If that circuit is faulty it could read too much current all the time.

I would expect the current being sent through some resistors and they actually measure voltage. Most likely a duff resistor or faulty solder joint then.

 

[atikovi]

Ningbo Dechang Electrical? Well there's your problem.

 

[Pablo]

There is cheap and really cheap

 

[DejaVue]

The original brush motor looks the same, though different markings. Here's the markings on it if that helps at all. Both old and brand-new motors do the same 6-second thing.

 

[Gyro Gearloose]

Pardon me for being Captain Obvious here, but have you considered replacing the board? Our newest vacuum will trip the brush motor when it winds up a rug or something rather than smoking the belt like our old vacuum used to do. My hunch is that the board is a rectifier and a time delay current overload breaker which has had something go out. It thinks it's always in an overload condition.

 

[DejaVue]

The only boards I see are used ones for $35. Would be more tempting if new. And then this might happen again anyway. There's plenty of ticked off people on the internet with this problem. I'd certainly prefer to fix this board than to hotwire it, (if hotwiring it is even possible if the motor is DC), but trying to figure out what to fix on it.

 

[LvR]

The original brush motor looks the same, though different markings. Here's the markings on it if that helps at all. Both old and brand-new motors do the same 6-second thing.

View attachment 126268View attachment 126269

So help me out here then .................. one motor is marked AC and the other DC?

If the original is in fact AC I also vote for simply hanging the motor off the AC line

 

[DejaVue]

So help me out here then .................. one motor is marked AC and the other DC?

The numbers on the old motor are half covered in rust, but there's enough to match it up with pictures of some used ones on ebay, and this Amazon listing: https://www.amazon.com/Hoover-Nozzle-Uh70400-Uh70401-Uh70402/dp/B00Y348LT6/
That's about the only listing I've seen for a new motor that doesn't cost twice+ as much as that and has the same markings as the old one. The handful of reviews on there say it worked great for them.

The markings in that listing, (pictures copied to post #7 above), match up with the old motor. However, the new motor that arrived from that listing is the motor in the OP. Both new and old motors do the same turn off after 6-second thing.

Here's an ebay listing for the same new motor in the OP. It says it's for Hoover UH72400. An internet search for that brings up pictures of the externally-same-looking Hoover Air Steerable vacuum. Hoover motor ebay

There's other motor listings around the internet for the various Hoover "Air Steerable" vacuum model numbers, vacuum model numbers grouped together for the same motor listings, (Uh70400, Uh70401, Uh70402, etc, that from external pictures all seem to be the same vacuum), and various of the motor listings for them have different markings. I assumed that's just due to Hoover using different manufacturers at different times.

Regardless of all that, the old motor does the same 6-second turn off as the new motor, so apparently I didn't need to buy a new motor anyway and could still use the old one. But it would still do the 6-second turn off, so that puts me back to can either motor be hotwired or how do I fix the circuit board.

It's a nice vacuum (when it works) by the way. It's not cumbersome, the steering function is useful, and, surprisingly, it's about as powerful as a Dyson.

 

[Marcozi]

The original brush motor looks the same, though different markings. Here's the markings on it if that helps at all. Both old and brand-new motors do the same 6-second thing.

View attachment 126268View attachment 126269

Notice the original motor says "60HZ"? It's an ac motor. The new motor is mislabeled.

 

[wpod]

What would be the duty cycle of the motor?

 

[LvR]

What would be the duty cycle of the motor?

60Hz is the frequency of the incoming electricity feed from your utility company - the voltage waveform follows a sinusoidal shape 60 times a second and has nothing to do with the motor at all.

The question is what is the original motor - AC or DC? ................... BOTH cannot be right/suitable for the application IMO.

 

[DejaVue]

Someone's going to want to see the original motor. Here it is.
If you think I can hotwire this one, great. Of course I'd prefer to figure out and fix the circuit board, but I don't know how to do that.

 

[LvR]

Someone's going to want to see the original motor. Here it is.
If you think I can hotwire this one, great. Of course I'd prefer to figure out and fix the circuit board, but I don't know how to do that.

View attachment 126321

Going off the actual markings on the motor, which is an AC motor, and assuming it is correct, should have no issue running directly off the incoming feed.

I have seen other vacuums with similar little pcb controllers and they have always been "soft starters" - iow - the motor starts at 0 rpm and slowly increases in speed to either full or a user variable and selectable maximum speed