EF: MOTORUN 2HP Static Phase Convertor

[Ttrevor]

MOTORUN 2HP Static Phase Convertor

Hello,

Last year my 30 year old Static Pase convertor stopped working, the 3 phase motor is 0.55KW / 0.74HP and drives a small lathe. When I switched it on the contactor in the Phase converter was being swiched on and off quite fast by the small Relay 1 oscillating on/off, and would not start the Motor.

I am not an electrician but I drew a Schematic of sorts but have only recently got around to buying a new set of Capacitors so I can try and repair it.

There are two switches on the converter, one selects the power and is a two position switch labelled (1/8HP - 1/2HP) for Low power and in the other position (1 - 2HP). The second switch selects High Start or Low Start . The two Start Capacitors are C4 and C5, and in the Low Start mode uses only C5 and in High Start uses both C4 and C5.

The Run Capacitors are C1, C2 and C3. in one position only 2 Run Capacitors are wired the Power select Switch switches in a 3rd Run Capacitor.

PROBLEM

I have looked all throgh my 12 Month old paperwork and I have found an error, due to redrawing the circuit and re numbering the three Run Capacitors in reverse order. 321 instead of 123 means that I am no longer certain which Capaitor was switched into or out of the circuit or wether it was switched in for the Low or High power setting. On one schematic I have drawn ( C1 10µF) switched and on the other (C3 6µF ) as switched.

I know for certain that C2 6µF is correct but I don't know which of the other two was switched in or out to change from 1/8th - 1/2 HP to 1 - 2HP.

Please, can anyone help by telling me wether increasing the Total Cpacitance to 22µF by switching in the 3rd Capacitor in parallel increases or reduces the power output and wether the Pair should Total 12µF or 16µF. also what is the purpose of this power switch.


Trevor

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