Adding a resistor in series with relay coil?

If you have a variac find out the minimum pull in voltage and the minimum hold voltage for your AC coil relay. To reduce the voltage on the AC relay coil just put a capacitor in series with the coil. The capacitor will have to be able to handle at least the full line voltage. I used this trick to reduce the voltage on the relays on my ground source heat pump. My original line voltage was 117/205 It went up to 125/250. The same trick is used in old multi speed ceiling or floor fans. Use the formula C= 1/(6.28 *F * Xc) Xc is the impedance of the capacitor ie 10-20% of the coil. Put an arc suppressor across the relay contacts.
 
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