Capacitor replacement questions

[®smpr_fi_mac®]

cap came from my 1958 PM 100 planer.  I don't know if the motor is original to the planer, but the paint scheme leads me to believe it is.  If so, I wouldn't be surprised that simple age killed it.

BUT...looking at the labeling on it makes me wonder.

The motor is a dual voltage; 110/220.  When I bought it it had an old 220 plug on it.  I assumed it was 220 and ran it that way.  The cap is labeled 110.  Could this kill the cap?  Tonight I'll open the motor and make sure it's set up for 220.  I've run it for a few hours on 220 and haven't seen any magic smoke.

If it's set for 110, I'll change it over to 220.

If it's already wired for 220, how do I explain a 110 cap in the motor?

Last question:  Where do I begin to search for a cap of the same rating? It's a 645-780mFd.

[TDKPE]

The start capacitor is running on 120V, regardless of the connection voltage.  

At 240V, both main run windings are in series, and the start winding is in parallel with one of those two windings (permanently), so all three windings are running on 120V.  

Connected for 120V power, the two main run windings are connected in parallel, and the start winding is, as before, permanently connected in parallel with one of the two main windings, so in the end, all three windings are connected in parallel and see 120V across them.

If the motor was connected for 120V but running on 240V, it probably wouldn't have lasted very long.  If connected for 240V and run on 120V, it would be extremely weak (torque curve depressed by a factor of 4).

But definitely do check for proper connection, which you can usually verify at a glance - assuming it's dual-voltage and reversible, if there are three leads going to each of the two mains (incoming power) leads (6 total), it's connected for 120V.  If there are leads connected to each other (only), it's probably connected for 240V.  There are many exceptions, especially if there is an internal overload device (Klixon type), but there should be a diagram inside the junction box or on the nameplate, so one way or another you should be able to verify voltage.

HTH

[®smpr_fi_mac®]

Ah! Thanks for that.

I have recent experience with running a 220 on 110--the jointer I own was wired for 220 but the seller had it on a 110 plug and couldn't figure out why it wouldn't work. I checked it and found it needed 220 and BAM it worked again.

[mike4244]

I bought capacitors at an electric pump supplier. Try yellow pages or google for one near you.

[®smpr_fi_mac®]

I purchased one from Grainger; they have a store near work.