Hi
I'm trying to work what power rating some resistors in series with a contactor coil need to be.
I've measured the coil at 4k7ohm, the actual resistors are 6k8ohm and a variable of 1k5ohm all in series with the coil.
minimum resistance = 4k7 +6k8 + 0 = 11k5
maximum resistance = 4k7 +6k8 + 1k5 = 13k
and using 240Vdc (yes DC as measured with my multimeter)
Following ohms law's W=(V x V) / R
I get...
so using minimum resistance (240 x 240) / 11500 = 5.009 watts
and using maximum resistance (240 x 240) / 13000 = 4.4307 watts
Does that look right or is that not the correct way to calculate the power drawn in a circuit with a coil ?
I'm trying to work what power rating some resistors in series with a contactor coil need to be.
I've measured the coil at 4k7ohm, the actual resistors are 6k8ohm and a variable of 1k5ohm all in series with the coil.
minimum resistance = 4k7 +6k8 + 0 = 11k5
maximum resistance = 4k7 +6k8 + 1k5 = 13k
and using 240Vdc (yes DC as measured with my multimeter)
Following ohms law's W=(V x V) / R
I get...
so using minimum resistance (240 x 240) / 11500 = 5.009 watts
and using maximum resistance (240 x 240) / 13000 = 4.4307 watts
Does that look right or is that not the correct way to calculate the power drawn in a circuit with a coil ?