Contactor Coil Data Question

[powersoff]

I have a AB bulletin 100-C Contactors pdf.

http://www.ab.com/en/epub/catalogs/12768/229240/229254/229461/229481/tab6.html

I am trying to intrepret the Coil Consumption data for an AC contactor.
For instance |50hz,60hz,50/60hz | Pickup |[VA/W]| 35/32 |

Does the VA rating correspond to 50hz and the W rating 60hz?
Why are the VA and W values different for the same contactor?

 

[waross]

VA is the Volts times the Amps, Watts is the Volts times the Amps times the cosine of the phase angle between the Volts and the Amps.
Google "Power Factor", another expression for the cosine of the phase angle, among other things.
Watts is the energy that you pay for, and more important for coils, the amount of heat radiated from the coil. Getting rid of the heat from a large number of coils may be a design consideration.
Another name for VA is the apparent power. Due to the induction of the coil, the current waveform lags behind the voltage wave form. But, the current as determined from the VA is the value on which you will base your fusing, conductor sizing and control transformer sizes.
The inductive reactance increases by a factor of 6 or 7 when the solenoid operates and reduces the air gap. Hence the large difference between pull in and holding values.

Bill
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