colchester lathe cooling pump

[ronan]

I decided to pull my colchester master out from the wall today to get the coolant pump and tank out and sort it out. The motor is three phase, which i suspected, but i have heard about converting these small motors to single phase using a capacitor across two of the phases.

How is this done eg. which two phases and how is the capacitor sized ?

 

[doubleboost]

 

[ronan]

Brilliant John, thanks very much. I don't know how i missed this video as i subscibe to your channel.

 

[Maker]

Have a look at this old thread. It's already wired as delta so you'll just need the capacitors. Brewdexta linked me to a really good page regarding capacitor sizing but I can't find it at the moment.

 

[ronan]

Have a look at this old thread. It's already wired as delta so you'll just need the capacitors. Brewdexta linked me to a really good page regarding capacitor sizing but I can't find it at the moment.

Wasn't here was it ?

http://www.electricneutron.com/electric-motor/use-three-phase-motor-single-phase-power-supply/

 

[ford34/2]

have a watch of John`s video, another Doubleboost production. May be of some help.
Stan

 

[Maker]

Wasn't here was it ?

http://www.electricneutron.com/electric-motor/use-three-phase-motor-single-phase-power-supply/

No, someone had experimented with various values of capacitor and measured the voltage of each phase to find the best values. As far as I know, no values of capacitor will give an equal voltage on each phase.

 

[ronan]

Yeah but the three phases are probably never exactly the same in any case. But using the 70uf/kw in the table above, volts x amps = watts, 240V x .22A = 53W or .053 KW. So 70uF/.053KW = 1320uF. So this is the value capacitor i need ?

 

[Maker]

Here's the page I had.

 

[graffian]

1320uf! I would guess more of the order of 5uf.
The motor I did like that is the Showa oil pump on my mill, I ran the motor for an hour or so and it seemed fine
[it din't get hot], I had a cap from a microwave oven between live and a phase.
So I stuck the pump back on my mill and left it on for a few hours[it runs constantly] and it was fine.
I will look and see what the cap is tomorrow.

You wire the motor with live and neutral as two phases and then wire live ->cap->third phase.

 

[ronan]

1320uf! I would guess more of the order of 5uf.
The motor I did like that is the Showa oil pump on my mill, I ran the motor for an hour or so and it seemed fine
[it din't get hot], I had a cap from a microwave oven between live and a phase.
So I stuck the pump back on my mill and left it on for a few hours[it runs constantly] and it was fine.
I will look and see what the cap is tomorrow.

You wire the motor with live and neutral as two phases and then wire live ->cap->third phase.

Yeah i knew it wasn't 1320uf, i reckon the units are wrong and maybe it was 1.32uf. I'll have a root around tomorrow and see what caps i can scrounge, there is an old telly here thats surplus to requirements, i'll open it and see whats there.

 

[Wendelspanswick]

Yeah i knew it wasn't 1320uf, i reckon the units are wrong and maybe it was 1.32uf. I'll have a root around tomorrow and see what caps i can scrounge, there is an old telly here thats surplus to requirements, i'll open it and see whats there.

Fluorescent light fittings can yield high value caps suitable for use with electric motors.

 

[graffian]

Yeah i knew it wasn't 1320uf, i reckon the units are wrong and maybe it was 1.32uf. I'll have a root around tomorrow and see what caps i can scrounge, there is an old telly here thats surplus to requirements, i'll open it and see whats there.

My oil pump motor is .16A 200V three phase. The cap is 1.2µF 2,100V metal cased thing.
It's wired as I posted above.
I don't know much about tellies, but I wouldn't have thought they had suitable caps in them.
If you buy one your looking for motor run caps.

 

[ronan]

ITS ALIVE. I had to go into town today, so popped into maplins to see what they had, surprisingly they did have motor run caps, i bought a couple, as they were cheap at five euros each. Bought one at 1.2uf and one twice that at 2.5uf. Fitted the larger one and the pump motor runs fine. I left it on for half an hour and while the motor did warm up, it didn't get hot. The capacitor didn't get warm in the slightest.

 

[graffian]

View attachment 68069

Looks good.

 

[Woody.v8]

Result

 

[ronan]

Yup, i'll drill a small hole to allow the wires into the terminals and epoxy the cap to the side of the motor. Can't do anything else really.

 

[graffian]

Yup, i'll drill a small hole to allow the wires into the terminals and epoxy the cap to the side of the motor. Can't do anything else really.

I tie wrapped the cap to the side of the contactor.

 

[Maker]

I tie wrapped the cap to the side of the contactor.

But where do you store your tie wraps?

 

[Woody.v8]

But where do you store your tie wraps?