capacitor mistry

hi. new to this forum
got this old motor, capacitor is leaking and was removed and disassembled but motor can still be running, CW & CCW when reversing the leads! with no need for manual head start!

supposed to be a 0.5 hp farm duty motor?

anyway, I am looking for a replacement for this capacitor although I can't read details on old capacitor and can't really tell which capacitor should I buy.
maybe you can help here..

also, how could it be motor is running without a capacitor and without manually turning the shaft? or might be there internal start capacitor inside?

thanks

I can almost read 45uF on the cap. Its a start cap, ensure the centrifugal clutch switch properly disconnects the cap.

You may find a 10uf run capacitor left in circuit may provide enough starting torque if the motor runs a blower, or grinding wheel, etc

johansen said:

I can almost read 45uF on the cap. Its a start cap, ensure the centrifugal clutch switch properly disconnects the cap.

You may find a 10uf run capacitor left in circuit may provide enough starting torque if the motor runs a blower, or grinding wheel, etc

Click to expand...

thanks for the reply. if I decide on getting new 45uF start capacitor used here with 220 volts, should it be rated for same voltage or 1.5 times 220 volts?
does 45uF seems correct for this rated power of the motor?

will continuity test to the capacitor 2 wires coming from the motor be the correct method to make sure clutch switch disconnects the cap(no connectivity while motor is running)? or I have to disassemble the cover to inspect clutch visually?

in your second line you are saying I might find a run capacitor inside if I disassemble the motor? did I get you right here? or you were suggesting I get a new start capacitor rated 10uF depending of its use?
anyway I am considering building a wood lathe out of this motor.

also, is that common that motor such as this one runs without a start capacitor and without any help?
thanks

johansen said:

I can almost read 45uF on the cap. Its a start cap, ensure the centrifugal clutch switch properly disconnects the cap.

You may find a 10uf run capacitor left in circuit may provide enough starting torque if the motor runs a blower, or grinding wheel, etc

Click to expand...

thanks for the reply. if I decide on getting new 45uF start capacitor used here with 220 volts, should it be rated for same voltage or 1.5 times 220 volts?
does 45uF seems correct for this rated power of the motor?

will continuity test to the capacitor 2 wires coming from the motor be the correct method to make sure clutch switch disconnects the cap(no connectivity while motor is running)? or I have to disassemble the cover to inspect clutch visually?

in your second line you are saying I might find a run capacitor inside if I disassemble the motor? did I get you right here? or you were suggesting I get a new start capacitor rated 10uF depending of its use?
anyway I am considering building a wood lathe out of this motor.

also, is that common that motor such as this one runs without a start capacitor and without any help?
thanks

In days of yore thee was an other class of small motors call split phase that didn't get their starting torque from a capacitor but rather from the resistance of a start winding. They worked the same as capacitor start motors but were for light duty applications. What you have may be a combination of the split phase and capacitance start/run.

45 microfarad is heavy for just run, these are more in 10 mfd range. Similarly, start caps are often 200-300 mfd.

Tom

This is a 1/2 hp 220v motor so a 45uf start cap is believeable. The same motor but wound for 120vac would need a 180uf cap.

As for the voltage just get a 240vac or higher cap.

If you do leave a 5 to 15uf capacitor permanently connected, you could easilly see 350+ volts on it, if the motor has a lot of turns on the aux winding.

Many small motors have lightweight aluminum start windings that are varely adaquate for starting the motor and adding a run capacitor will not improve efficiency.

No i did not intend to imply the motor already has a run capacitor. Verify the centrifugal switch has continuity and at speed it disconnects the start capacitor.

johansen said:

No i did not intend to imply the motor already has a run capacitor. Verify the centrifugal switch has continuity and at speed it disconnects the start capacitor.

Click to expand...

many thanks for the assistance
I will replace the capacitor, assuming it is a start cap. and check if the clutch engages after start.
I will not add another cap as permanent running cap, but to keep it at its original setup, probably this is the best thing to do.

TDegenhart said:

In days of yore thee was an other class of small motors call split phase that didn't get their starting torque from a capacitor but rather from the resistance of a start winding. They worked the same as capacitor start motors but were for light duty applications. What you have may be a combination of the split phase and capacitance start/run.

45 microfarad is heavy for just run, these are more in 10 mfd range. Similarly, start caps are often 200-300 mfd.

Tom

Click to expand...

thanks
I will try to open the motor to see what system is inside and see if it is a split phase. have first to see some video about split phase and see how it looks

That cap does not look like it went with that motor. My guess is that this was built as a split phase and at some later point someone tried adding a capacitor to try to overcome the limitation of split phase motors having low starting torque. That would not have worked correctly and likely led to the failure of the capacitor.

Jraef said:

That cap does not look like it went with that motor. My guess is that this was built as a split phase and at some later point someone tried adding a capacitor to try to overcome the limitation of split phase motors having low starting torque. That would not have worked correctly and likely led to the failure of the capacitor.

Click to expand...

hi
see picture number 3, it shows motor has a built in housing attached to the body of the motor to hold the capacitor, so I assume it was originally built to have a cap.

Reading this post I doubt very much if there is a Cap. inside! I've seen strange locations for Caps. including in the motor base. Plus the side of the capacitor would make it difficult to put it inside. The size you think it is 45ufd seems about right for a 1/2HP motor. Not sure how you determined the cap was bad other than it's leaking but under light start load it just might have enough capacity to start the motor.

Froneck said:

Reading this post I doubt very much if there is a Cap. inside! I've seen strange locations for Caps. including in the motor base. Plus the side of the capacitor would make it difficult to put it inside. The size you think it is 45ufd seems about right for a 1/2HP motor. Not sure how you determined the cap was bad other than it's leaking but under light start load it just might have enough capacity to start the motor.

Click to expand...

hi
cap. did literally fill apart just by taking it out of housing.
motor is running same thing even after removing it.

A capacitor start motor will start and run fine with reduced starting torque
by shorting the leads to the capacitor, provided everything else is working properly.

Bill

hitandmiss said:

A capacitor start motor will start and run fine with reduced starting torque
by shorting the leads to the capacitor, provided everything else is working properly.

Bill

Click to expand...

thanks bill
it is strange motor is starting without the capacitor and without shortening the leads, that means this cap is connected by parallel? anyway I assume there is another starting technique for the motor inside.
I tried opening the motor to investigate what is inside but it seems the capsule is tight and am afraid it will cause some harm to this old motor. the fan is already broke and seems very old and dry!
what I did was testing contiuity to the 2 leads to the capacitor (without the capacitor) and the motor do have sort of governor that shuts off electricity to the leads to capacitor just after motor starts by shutting off electricity and hence no continuity.

Yes there is a centrifugal switch that removes the capacitor from the circuit after motor is up to speed no longer needing the start Cap. You said the motor will reverse by switching the leads, what leads?

Froneck said:

Yes there is a centrifugal switch that removes the capacitor from the circuit after motor is up to speed no longer needing the start Cap. You said the motor will reverse by switching the leads, what leads?

Click to expand...

hi
thanks
I meant by switching the leads of the main motor cable (neutral and power I guess are called) that connects to the wall electricity.

re mentioning that motor runs even without the capacitor!
have not tried yet running motor with capacitor wires closed together (without the capacitor itself)

You have 220VAC to neutral? I have no idea what kind of power you have in your country. I'm assuming the other line is not neutral. In the USA there are places where 3 phase comes off a common transformer, 2 power lines and a neutral for single phase is wired to each user on that shared transformer. Here the voltage is then 208VAC. That is because the 2 phases are not 180 degrees opposite each other. That also might be the reason your motor will start without a Capacitor. 208 is of course what we have in the USA but the voltage you have 220VAC can be just what is available in your country for 3 phase power and you getting one set of lines connected as I mentioned above.

Most places have 220/230 to neutral, and 380/400V line-to-line. That comes straight from distribution 3 phase.

The housing is at least painted the same color as the rest of the motor, so it may well be original, as I see just one color on the thing.

Sometimes a motor will in fact start, usually not very well, without the actual start circuit, due to some small difference in the winding or iron configuration. Will have nearly zero torque , usually. Most motors will not start at all without a working start circuit, they just sit there and hum, with a very large current flowing.

Reversing the input by reversing the power wires should have absolutely no effect. Alternating current already does that 50 x per second (60 in US and Canada).

As far as explaining your motor that starts both ways, I got nothing....

I must admit I have little knowledge of power in other parts of the world and probably most are similar in that they might have some type of grid as we do in the USA. I also know that California had 50 cycles many yeas ago. However in 2005/06 I spent some time near Kazan Russia. Woman there did my laundry in the bath tub, feeling bad I had her select a washing machine, purchased it and had it installed in her bathroom. Unfortunately we discovered that when the washing machine was running we could not use any other electrical device including the lights because anything additional would trip the breaker. She said she would have to contact someone to have a larger breaker put in. Took a few days so when we did laundry we went out to eat. Time came for someone to do what ever was required, she went to work I waited the arrival. The man removed the secured cover on the breaker panel in the hall and when wiring has been complete to notify them and the cover will be replaced and left! Seems they didn't care who did the wiring I took it upon my self to do it. The panel was fed by 2 large wires 100 or 200mcm can't remember exactly that continued to the next junction along with another pair of the same size that were were not used. No neutral other that the rigid conduit. Breaker was 2 pole. Thought somewhat fluent in Russian at this time it was basically every day talk but I managed to locate an electrical supplier and buy a larger breaker along with some tools and a cheap Chinese VOM. Completed the installation and the man when called replaced the cover. The wiring in side the box resembled a pile of spaghetti!! The typical plug in the bathroom being 2 round pins that could be inserted any way as there was no polarization. However it was of the newer type that had a ground, the plug had a metal ring so that when plugged into the slightly recessed socket contacted fingers that made the connection to ground. Other outlets in the apartment would accept the "grounded" plug but were not slightly recessed and nothing made contact. I also noticed all power was supplied throughout the city via 4 wires and seem to be 2 phase though I had no way to confirm that. When measuring voltage to ground both sides of the outlet were 120VAC to ground. What they might have in Israel I have no idea but if similar would explain motor starting and reversal. Not 2 phase because that would have a 180 degree separation. Also working around NYC I have seen many applications of 208VAC power that was 2 of the 3 from a 3 phase source.