I've had a situation in my plant recently where we have been blowing fuses on some of the power factor correction capacitors on our large 5kV motors. Our typical power factor for the plant is about 80-90% and we DO NOT pay a power factor penalty with the utility.
Recently when the fuses in these capaciotrs have been blowing we have not had the replacement fuses in stock. We needed to get back up and running so I stated that since we did not pay any sort of PF penalty then to go ahead and run the motor without the Caps.
A production manager noticed that the motor running without the Caps caused the current on the motor to increase (Current monitored by CT's) and became concerned. He took the numerical current increase he saw and performed a calculation and stated that by not having the capacitor this increased current is costing us some $150,000.00 in our power bill.
I tried to explain to him that the increase in current he is seeing is due to Reactive Amps that were coming from the capacitor before but now are coming across the line from our plant power. I explained however that these amps were only Reactive amps and were amps that we did not pay for. I tried to explain the whole concept of power factor and Active (kW) vs Reactive (kVAR) amps with a power triangle but he is still not believing me.
Just so that I am not missing anything, am I correct by stating that the increase in amps he is seeing are reactive amps and that there is no direct corrolation between these amps and an increased electric bill. The only way there would be an increased electric bill is if we paid a PF penalty which we do not, so there is no increase here either.
Recently when the fuses in these capaciotrs have been blowing we have not had the replacement fuses in stock. We needed to get back up and running so I stated that since we did not pay any sort of PF penalty then to go ahead and run the motor without the Caps.
A production manager noticed that the motor running without the Caps caused the current on the motor to increase (Current monitored by CT's) and became concerned. He took the numerical current increase he saw and performed a calculation and stated that by not having the capacitor this increased current is costing us some $150,000.00 in our power bill.
I tried to explain to him that the increase in current he is seeing is due to Reactive Amps that were coming from the capacitor before but now are coming across the line from our plant power. I explained however that these amps were only Reactive amps and were amps that we did not pay for. I tried to explain the whole concept of power factor and Active (kW) vs Reactive (kVAR) amps with a power triangle but he is still not believing me.
Just so that I am not missing anything, am I correct by stating that the increase in amps he is seeing are reactive amps and that there is no direct corrolation between these amps and an increased electric bill. The only way there would be an increased electric bill is if we paid a PF penalty which we do not, so there is no increase here either.