I'm rebuilding a hardinge CHNC...

The machine will be single phase with a VFD for the spindle.

I just found out the coolant pump is three phase. It is 1/10 or 1/20 hp.
Using a clamp type ampmeter it just tickles the needle on the 6 amp full
scale setting. I'll guess .1 to .2 amp per phase.

So, would it work to just use a run cap accross L1 L2 L2=wild legto start
this thing? How large should I try?

If needed, I could use a start delay timer and bring in a cap accross L2 L3.
Need this? How large?

Karl

Try 3 to 5 MFD and make sure it is not staring under load, once it spins up
to speed close the coolant valve . Be carefull not to allow too much back
pressure so that it slows the pump down. You will need to leave the
capacitor online.



"Karl Townsend" remove .NOT wrote in
message k.net...
I'm rebuilding a hardinge CHNC...

The machine will be single phase with a VFD for the spindle.

I just found out the coolant pump is three phase. It is 1/10 or 1/20 hp.
Using a clamp type ampmeter it just tickles the needle on the 6 amp full
scale setting. I'll guess .1 to .2 amp per phase.

So, would it work to just use a run cap accross L1 L2 L2=wild legto
start this thing? How large should I try?

If needed, I could use a start delay timer and bring in a cap accross L2
L3. Need this? How large?

Karl

Item 7568509552 on ebay is a 1/8th hp single phase VFD for $20

Karl Townsend wrote:

I'm rebuilding a hardinge CHNC...

The machine will be single phase with a VFD for the spindle.

I just found out the coolant pump is three phase. It is 1/10 or 1/20 hp.
Using a clamp type ampmeter it just tickles the needle on the 6 amp full
scale setting. I'll guess .1 to .2 amp per phase.

So, would it work to just use a run cap accross L1 L2 L2=wild legto start
this thing? How large should I try?

If needed, I could use a start delay timer and bring in a cap accross L2 L3.
Need this? How large?

Karl

"RoyJ" wrote in message
.net...
Item 7568509552 on ebay is a 1/8th hp single phase VFD for $20

Thanks for the tip.

Don't outbid me.

Karl

NOT A CHANCE!!

Karl Townsend wrote:

"RoyJ" wrote in message
.net...

Item 7568509552 on ebay is a 1/8th hp single phase VFD for $20


Thanks for the tip.

Don't outbid me.

Karl

I see you bought it!

RoyJ wrote:

NOT A CHANCE!!

Karl Townsend wrote:

"RoyJ" wrote in message
.net...

Item 7568509552 on ebay is a 1/8th hp single phase VFD for $20



Thanks for the tip.

Don't outbid me.

Karl

On Wed, 07 Dec 2005 21:55:22 GMT, "Karl Townsend"
remove .NOT wrote:

I'm rebuilding a hardinge CHNC...

The machine will be single phase with a VFD for the spindle.

I just found out the coolant pump is three phase. It is 1/10 or 1/20 hp.
Using a clamp type ampmeter it just tickles the needle on the 6 amp full
scale setting. I'll guess .1 to .2 amp per phase.

So, would it work to just use a run cap accross L1 L2 L2=wild legto start
this thing? How large should I try?

If needed, I could use a start delay timer and bring in a cap accross L2 L3.
Need this? How large?

Karl


Don't know if it'similar to your pump but the 1/8 HP
centrifugal suds pump on my Schaublin mill needs 16uF start and
4uf run capacitance. Because of their lower efficiency these very
small 3 phase motors are more difficult to single phase convert
and have dead lousy starting torque. Fortunately this is not much
of a problem with a centrifugal pump unless you're you're using a
high viscosity neat cutting oil.

Because it's a centrifugal pump minimum torque demand is with
the delivery turned OFF. In practice it makes precious little
difference.

Jim