need help with my pump!

[ieezitin]

Well guys I installed the capacitor and orientated the pump in the position that it should be  run and turned it on and it still gives off a hum and draws current that makes my lights go out. So now what do I do?

[John Hill]

Either the motor has totally karked or there is something preventing creation of the necessary starting torque.

Some motors have a switch that closes when the motor stops and that closes the starter circuit, when the motor begins to spin the switch opens.  If the switch fails to close the motor will not start.

So, peer into the end of the motor and see if you can find anything that looks like contacts etc, these switches are often not much more than some bits of bent metal with a light spring attached.

If the spring is broken there is no incentive for the switch to close, if the contacts are burned and not making contact that could be another reason for no starting circuit.

Be careful with the capacitor, it can be charged up to lethal levels!

[Bernd]

Is the motor and pump free wheeling when assembled? I would have to say you have a binding problem somewhere.

Bernd

[ieezitin]

Thanks to all again for helping.

John. I will look for the spring switch thing. Great advice about the stored energy in the capacitor. Just what is the right way to discharge the energy?

Bernd. a lot of people have mentioned the same thing. What puzzles me is that when I spin the motor by hand I feel a little resistance but! that’s the bearings, I cant feel lumps or get the rotor stuck.

Thanks to all.   Anthony.

[Darren]

Great advice about the stored energy in the capacitor. Just what is the right way to discharge the energy?



Thanks to all.   Anthony.

Simply grab both ends of the capacitor in each hand and it will discharge quite nicely. When you have stopped dancing and the burning smell drifts away you will know that the process has completed ....



Or if you prefer,

Use a wire and resistor across the terminals to discharge the cap. The resistor slows this down to put less strain on things.

The second idea sounds good to me, but the choice is of course yours as always .....  

[ieezitin]

Darren.

Thanks pall  I shall try the first idea as a need a different atmosphere in the shop anyways, I am getting tired of way lube and cutting fluid aroma.
 

If I don’t like the result I should try the second but a resistor is something I may not have but! If I were to carefully short out the terminals to a ground rod I have buried in the shop would that work?

Anthony.

[Darren]

Well a bit of resistance is the "proper" way to do it, that's why your body works so well.

But then I often am too lazy to go and look for a resistor and just use a piece of wire. Just don't tell anyone or there will be a riot.... 

You don't need to short it to ground, just across the terminals, just flick it and keep flicking it till the sparks stop. Then wrap some wire around the terminals cos caps can sometimes re-charge a little bit. I say a little bit, it can still hurt.

[John Hill]

There is still a bit we dont know about this problem but maybe this will help us along the way:

Get a mains light globe, put it in a socket and wire it across the capacitor (i.e. one wire from the light socket is wired to one terminal of the capacitor and the other light socket wire connected to the other capacitor).  Then try the start again.

If the motor was/is working properly the light will come on briefly as the motor gets up to speed then it will go off.  Also, provided the light bulb is good it will discharge the capacitor.

If the starting switch is not closed (as it should be when the motor is stopped)  the globe will never light, so that is useful information.

N.B. Take no chances with the capacitor and always consider it charged and lethal to the touch.

[ieezitin]

John.

I will do this tomorrow I sent a little drawing of what I think is your idea as to do the light bulb thing.

This way I will have the pump stripped down again and I will probably tear into the bearings and such. But first I will try your idea.

Thank you   Anthony.

[Bluechip]

Anthony

That won't do anything. The lamp terminals are shorted. It won't light up!

As no-one has posted a circuit of a 'generic' single phase, capacitor start motor, I will e-mail you some info. if you want.

Can't be bothered to post pics. on P-bucket    copyright stuff anyway ..
 
Dave BC

[Bluechip]

Anthony

On reflection ...

As this motor was oil-immersed, I doubt if it ever had a start switch. Electrical oil is a very good insulator, it would inevitably get between any start switch contacts, and never start.

Could be a capacitor start/run motor. Fluids take some power to pump, so it adds up there too.

Looking at the pics. it MAY be that the configuration you have is like this:



In which case you can

Remove the capacitor first, and

Meter, on a low resistance range, between yellow and white. I guess you should get from about 50 to 200 ohms. Typical, not absolute, varies!
This checks the start winding.

Meter between red and white, once more a similar value. They will almost certainly be different.
This checks the run winding.

If  one or more of these is a very high resistance, above 1000 ohms or so, that winding is probably done for.

It is quite normal not to see all the connections. They are often done at the end of the windings, then sleeved and buried. Just to make life easy.

Also meter between red and green, must be well above 1Mohms. Ditto white and green.

This does assume that the diag. is OK

It's non-destructive, worth a try, and posting the results.

Bit of practice with your meter ..  

Dave BC

[ieezitin]

Dave.
I thank you for the little sketch, drawings are always the most important part of any explanation.

Now after reading again John Hills explanation I think as you look at the little crap o cad I got it wrong on what he was trying to get over. My fault not his.

I have printed out your idea and to the shop in the morning I will go give this a shot. your right this is a great chance for me to do a real time experiment with my meter.

I have other questions but I will wait until I give the  report on this exercise. Thank you.

Anthony.