Ignoramus9179 wrote:

On Mon, 15 Aug 2005 22:30:24 -0500, Martin H. Eastburn wrote:

Ignoramus9179 wrote:


I built a self starting phase converter with a 10 HP idler and two 92
mF capacitors. It works great and starts in under 2 seconds.

I also have a very similar looking Century 7.5HP motor. They 10 HP and
7.5 HP look similar.

This 7.5 HP motor would NOT spin up from two other capacitors. If I
wire it with three capacitors (I have 5 total, 2 already used in the
main phase converter), it would spin up, but it takes it about 5
seconds to do so and it warms up appreciably. What gives?

Another tidbit is that the 7.5 HP motor starts just fine from 3 phase
output of my phase converter. I do not think that it is a bad
motor. Maybe some caps out of these three are in bad condition.

i


The inductance of the winding is different. The motor works.
Different caps than those used would work.


Do you mean different, as in having different capacitance?

i

The caps are trying to counteract the winding inductance.
So if the motor changes between models, companies, Years then the inductance
is either the same, lower or higher. One in three you have to change the cap value.

It is the same for a larger or smaller motor. (also naturally)

Martin

--
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

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