Electric lawn mower seams dead, possible to rescue?

[mxnerd]

Couldn't start the mower and the motor kept humming. In one point, the electric socket the mower plugged into smoked, not the mower itself.

Changed to another socket and it kept humming but still won't start, and finally it won't even make humming sound and was completely quiet.

Unscrew the cover of mower and found a cylinder object on the circuit, pulled it out and it looks like this. Suppose this is the part it burned out?

What is this called? Can I buy it somewhere and fix it?

 

[drnickriviera]

looks like a start capacitor. should have some writing on the side of the black case still in the mower

 

[mxnerd]

OK, found the label on the other side of the case. It's a CBB60 45uF 250V AC capacitor.

Should be fixable? If I can't find exact spec product, can I use something a bit off or better in spec?

Like 40 ~ 60uF / 240V ~ 260V AC capacitor?

How do I know the motor is good before I order the capacitor?

 

[pcgeek11]

I did a web search for this " CBB60 45uF 250V AC capacitor " and came up with pages of hits...

What brand and model of Lawnmower would help a lot.

 

[drnickriviera]

I'm no EE, but without a multimeter and some kind of wiring diagram, i doubt you can test the motor. It isn't a good sign that the motor no longer buzzes (possibly burnt a winding?) You can go with a higher voltage cap, but i'd stick with the same uf.. There should be tons of 45uf 370 or 440V caps out there. All metal case caps listed as a run cap will be fine as long as it will fit.

I'm thinking the start cap blew, the motor needs it to generate the torque it needs to start up that's why it humms. Motor draws massive current trying to start up burning out the plug. When you fixed the plug and tried again...massive current something has to give possibly burning out a winding. Maybe it has some thermal protection that will reset itself or need to be reset.

 

[Greenman]

My guess would be you cooked the motor.
I'd also be inclined to check out the outlet that smoked and figure out why the breaker didn't trip.

In the world of electricity, it's always best to stop a device that isn't operating properly before the fire starts.

 

[mxnerd]

It's a Sun Joe mower.

I do have a multimeter and I did worry that motor is out.

Will cut the wire and test the continuity.

 

[mindless1]

Unfortunately Sun Joe's manuals don't seem to provide as much in the way of parts diagrams and numbers as some brands, to get a better idea of what else is in this mower to check and/or what parts can be acquired at reasonable cost, or am I mistaken?

You could have replaced the capacitor when it first showed the symptom but once it drew so much current to burn the outlet and possibly fry the motor, it's likely not repair worthy, considering you can get a corded electric mower new for about $100.

That's unless it just blew a fuse or tripped a breaker, maybe fried an inexpensive rectifier diode pack... keep looking around for one, there probably is a fuse or breaker somewhere. The motor itself wouldn't need the diodes but some control/safety circuitry or ??? might.

 

[C1]

Looks like the capacitor start Sun Joe replacement motor is readily available for $50 before tax and shipping expenses.

The function typically of the "start capacitor" is to provide a shifted or offset electric field for the purpose of rotating the "rotator" or armature. My experience has been that these capacitors pretty much last forever. (You could do a primitive test using an ohm meter to test the capacitor for fully open or fully shorted condition.)

Otherwise, check the motor for burnt windings (visual & smell test).

There's a chance that a lose wire was the initial cause, but also now a thermal safety switch or fuse has disconnected the motor circuit.

Oh ya, sometimes you can just visit a hardware store like Lowes or HD and take continuity/resistance readings off critical spots on a floor unit when nobody is looking. (Bring you screw driver and multimeter with you.) Compare those results to your current unit to assist problem diagnosis.

 

[mxnerd]

Well, could not locate my multimeter at the moment.

If the motor is out eventually, I think I'll buy a reel push mower instead.

 

[NutBucket]

As stated, get a generic capacitor and see if that does the trick. It's a very common failure.

 

[mxnerd]

Finally found my multi-meter.

Unscrewed the red & black wires from the white connector, test it and he motor's ohms read 1.6 ohm, is it good?

BTW, this is a corded mower.

 

[pcgeek11]

To test it you will need more than a DMM.

A megger or megohmmeter would be in order to see if the winding insulation is breaking down when loaded.

The little battery in the meter isn't going to tell you much unless it is open or shorted.