Start capacitor

[fishhh4]

   

   

   



My old 1/2 hp Peerless motor blew the start Capacitor on my compressor. It runs on 230 volts.
This one has the same dimensions... Think it will fit the bill?
Temco from Amazon

[lkomroff]

That does not fit the bill.  It is hard to tell the value (range) from the pictures but based on what I can make out, one of these capacitors
will work. I am sure you can find in other online sources too. If you go with a higher voltage rating, the cap will be larger so it might not fit in the space. It wont hurt to go with a higher voltage rating but make sure the dimensions will work.  The mFd or uFd range should be the same or close to the original.

Larry

[TDKPE]

This one has the right capacitance and voltage, though I don't know about the size.  You could always mount it externally if you have to though, as long as you protect fingers against contact with exposed terminals. 

PMJ378 - Packard PMJ378 - 110-125V Start Capacitor (378-455 MFD) (supplyhouse.com)

[fishhh4]

After further research and your input lkmroff   It looks like I need something in the 378 to 4 something range for the mfd rating. Are mFd and uFd ratings the same thing then?
On the old one, there is no mention of 230 volts. It says 110/125 Vac, though the motor is powered by 230 volts. Not sure that the old one is original to the motor.
The old one was 1.81" round by about 3.5" tall. I think there is room to fit a slightly larger one.

[fishhh4]

This one has the right capacitance and voltage, though I don't know about the size.  You could always mount it externally if you have to though, as long as you protect fingers against contact with exposed terminals. 

PMJ378 - Packard PMJ378 - 110-125V Start Capacitor (378-455 MFD) (supplyhouse.com)

Tom, that one would fit. The motor runs off of 230 volts though. I know the old one says 110-125 but that's not to say someone stuck the wrong one in there at one time. It has started flawlessly for the last three that I have had it.

Edit to add:
just saw this on a description... Can the uf rating be obtained by the 9 amp motor label description... dumb electrical mind is curious.
2.As 220v or 230v single phase motor, run capacitor can be estimated Approximately as C = 0.03* Power(watts) uF

3.As 110v or 125v single phase motor, run capacitor can be estimated Approximately as C = 0.1* Power(watts) uF

[TDKPE]

Tom, that one would fit. The motor runs off of 230 volts though. I know the old one says 110-125 but that's not to say someone stuck the wrong one in there at one time. It has started flawlessly for the last three that I have had it.

That motor is 115/230V rated.  The start winding is in parallel with one of the two main windings, so regardless of which voltage it's configured for (through reconnection of the internal leads), both main windings and the start winding are actually running at 120V.  

Imagine two 120V light bulbs.  Wire them in parallel and connect to 120V and each bulb 'sees' 120V and everything is Jake.

Reconfigure the wiring so the two bulbs are in series but connect to 240V.  Now each bulb drops half the voltage (120V), so again, they're both running at 120V and everything is Jake.

Now add a small bulb in parallel with one of the two big bulbs and do that mental exercise again.  The small bulb will 'see' 120V whether the two main bulbs are in series on 240V or in parallel on 120V.  

The start winding is wired in parallel with one of the two run windings, but it's only in the circuit for a fraction of a second while it starts, until the centrifugal switch opens and takes the starting winding and capacitor out of the circuit.  Since the start winding is in parallel with one of the two run windings, it will 'see' approximately 120V while starting regardless of the voltage the motor is connected for.  So a 120V capacitor is what it needs, even configured for and connected to 240V power.

The EE's out there are lifting an eyebrow 
 because the voltage dropped across each winding on 240V isn't exactly the same, at least until the start winding cuts out, but it's close enough for this discussion.

[fishhh4]

Thanks Tom, I ordered this one...I appreciate your input. Pulled the trigger a second ago. Got the oilless one at a church I am flipping... NEED this one at my home shop. Gots to blow up the tires on the snowblower occasionally lol
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