Capacitor

This is not a plc question but hoping you guys can help. My boss would like to lower the in-rush current on an 120 VAC motor. The motor never had a capacitor on it before, can one be installed in series? Some of the stuff I have read says to size 50% larger on voltage and a formula of 2655xI/V to find the μF.

Install a soft-start?

What is really needed from you is a copy of all the detail from the motor name plate, along with what is the load connected to the motor.

Well my question is can a capacitor be installed on a 120 VAC motor with one set of windings,and will it reduce in-rush current

You should probably ask a motor shop, but except for power factor correction, it doesn't sound like a viable idea.

Nick.Ferguson said:

Well my question is can a capacitor be installed on a 120 VAC motor with one set of windings,and will it reduce in-rush current

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Yes, but only because the capacitor has internal resistance. ESR. This is not the correct way to do it. Capacitor will have a short life.
A VFD is about $100.00 for a small motor. This is the best way.

Well my question is can a capacitor be installed on a 120 VAC motor with one set of windings,
YES you can if you want.

and will it reduce in-rush current
PROBABLY NOT - you are just adding a load and one that has its own in rush current in addition

Reading between the lines -
increase your wire size you are having line volt drop problems.

Further help requires information you did not supply. Please supply copy photo of motor nameplate and describe the driven load OR
supply crystal ball

Dan Bentler

Well my question is can a capacitor be installed on a 120 VAC motor with one set of windings,and will it reduce in-rush current

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Simple answer, yes. Complex answer, it depends. What happens is the voltage and current will be reduced at the motor winding(s), depending on the capacitive reactance value introduced. It also reduces everything else, HP, torque, etc.

Well my question is can a capacitor be installed on a 120 VAC motor with one set of windings,...

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Yes to this part of your question. You can install about any device you want to, but whether it will help you depends on what you are trying to do.

and will it reduce in-rush current

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To reduce the in-rush current, you have to spread the motor "starting current" (the power it takes to overcome the inertia of the motor AND driven load) over a longer time period. An AC capacitor will not do that because it charges and discharges 60 times per second.

Starting the motor at 0 speed and slowly increasing to 100 % full speed is probably the best way to reduce motor starting current. A small soft-start electronic motor starter will do that, but you may have to change out your motor for a different type.

Thanks for the help, that was what I was thinking also but I wanted others opinions.