Professional Manufacturer of AC Motor Run Capacitors, Motor Start Capacitors in China.

home > News > Recommended Motor Start Capacitors for Single Phase Motors

News

Recommended Motor Start Capacitors for Single Phase Motors

Capacitors are manufactured, by using etched and formed pure aluminium foils (%99,99), seperated from each other with a low dencity, dielectric paper, inpregneted with a special electrolyte. Capacitor elements are fixed to the bakelite case, by filling the space between them, with a bituminous compound (softening point 110C min.).

Poles brought out to single or double, fast-on terminals. On requested supplied with end cap, bipolar cable, discharge resistance and metal mounting bracked.

- Application

In a fractional horse power single phase motor, in order to create a high starting torque, it will be necessary to displace the phase of the auxiliary winding by 90 degrees from the main winding, to get a rotating field. This will be achieved by connecting a motor start capacitor in series with the starting winding. This capacitor and the starting winding will be disconnected automatically, as soon as the motor reaches about %75 of its synchronious speed.

With a suitable choosen motor start capacitor, a loaded single phase motor will reach its full speed in approx. 3 seconds.

A table for start capacitors suitable for different HP ratings of 220 Volt AC 50/60 Hz single phase motors is given below.

Motor Rating Motor start Capacitor

Motor Rating Motor start Capacitor
(HP) (MFD)
1/6 HP 20-25MF
1/5 HP 30-40MF
1/4 HP 40-60MF
1/3 HP 60-80MF
1/2 HP 80-100MF
3/4 HP 100-120MF
1HP 120-150MF
1.5HP 150-200MF
2HP 200-250MF
3HP 250-350MF

related keywords

related posts

One Comment to “Recommended Motor Start Capacitors for Single Phase Motors”

  1. Collin Pestana April 23,2012 06:02 AM #

    I have an old automatic paper cutting machine which is operated by a single phase motor rated 220Vac 50/60Hz 400w. We have been using it more than 20years and motor been recoiled before (don’t know how long ago). Lately we stopped using it because there are 2 Start Capacitors in series with starting coil at least one will blow after less than 1 day. I understand that the Start capacitors on normal cycle will cut-off almost immediately after cycle starts. I found that in this case the capacitors are engaged for the whole cycle using a multimeter. After less than 10 cycles one capacitor slightly heating up. Since we bought this machine 2nd hand we don’t have the wiring diagram. Is this because of the motor not cutting of the capacitor load or motor winding starting to deteriorate or something else. Please help

Leave a Reply