Sustained Over Voltage Long term effect
Sustained Over Voltage Long term effect
(OP)
Guys, Did anybody come across any study on the effect of Sustained over voltage in a 3 phase 4 wire 60 Hz electrical system?
The actual voltage of the system, when measured, was found to be above 500/290 volts. The nominal rating is 480/277 volts 60 Hz.
What long term (3 months, 1 year) effects the overvoltage will have on the Cables/wires, Ballasts and MVLamps or Metal Halide Lamps and Incadescent lamps.
The actual voltage of the system, when measured, was found to be above 500/290 volts. The nominal rating is 480/277 volts 60 Hz.
What long term (3 months, 1 year) effects the overvoltage will have on the Cables/wires, Ballasts and MVLamps or Metal Halide Lamps and Incadescent lamps.






RE: Sustained Over Voltage Long term effect
Possible effects:
cables/wires: none
ballasts and MVLamps: will run hotter and may reduce lamp life
Metal halide lamps: higher output and shorter life
incandescent lamps: higher output and shorter life
RE: Sustained Over Voltage Long term effect
Thank you for your quick and valuable response. The volatge is measured at supply end.
Utility supply volatge is also more than 10%. Normal 4160Volts, measured 4300 volts.
You are right about cables because cable are rated for 600 volts.
marvin
RE: Sustained Over Voltage Long term effect
If you have Kollmorgen 460 volt servo drives exposure to 500 volts **WILL** blow them up! Somehow, their engineers are firmly convinced that power plant voltage in th U.S. is only 460 volts +-20 volts.
You really only have to worry about electronic equipment and any HVAC stuff that runs overnight when the voltage is naturally high.
RE: Sustained Over Voltage Long term effect
Can you adjust the taps on your transformer?
RE: Sustained Over Voltage Long term effect
I agree that the 4300 voltage is within 5% . Actually the voltage is 4400 which is above 5 %. First I would like to have the meter calibration cheked and the data electronically recorded for over 3-4 days.
Before approaching utility I want to find out if other users had any problem with sustained high voltages or any study about this problem.
Transformer Tap change is the solution I am going consider if the over voltage continues longer than 4-5 days.
RE: Sustained Over Voltage Long term effect
Thank you for the relevant information. I will visit the link and read the details. I really have to worry about electronic ballasts and other elctronic devices.
marvin
RE: Sustained Over Voltage Long term effect
RE: Sustained Over Voltage Long term effect
On the other hand, when we note MCC bus voltages of 440 V, they don't see much problem with that because "it's always been like that". But in reality, the motors would be happier at 500V than at 440V.
110% of 480V is 528 V.
110% of 460V (motor nameplate) is 506 V.
As mentioned above, if you want voltage to be in nominal range at full load, you have to accept some increase in voltage at no-load or low load.
RE: Sustained Over Voltage Long term effect
As I stated before, high voltage is more of a concern with electronic devices such as CNC, servos, and ballasts.
RE: Sustained Over Voltage Long term effect
Thanks. I agree with you. About motors. Motors have good insulation. Also are characterized by Inertia and also there is back emf to match the supply voltage. The speed is not going to be affected by higher voltage.
The devices I am worried about are solid state, electronic devices and lamps that are affected by higher voltages.
Here the voltage of 500 volts is not matter of concern. The voltage goes 510 & 520 volts for a good amount of Time. That may not be good for other devices.
Marvin
RE: Sustained Over Voltage Long term effect
Thanks for your reply. 500 volts at no load or light load is expected.
What about 510-520 volts at light load for other devices for 2-3 hours everyday?
Marvin
RE: Sustained Over Voltage Long term effect
You are right Ballasts, UPS , incandescent lamps need to be addressed when overvoltage continues for appreciable time.
Not motors.
Marvin
RE: Sustained Over Voltage Long term effect
A lot of electrical utility primary line capacitors are either on line all the time or use timer control. This could be a bit of a problem at lunchtime of if the timers are off time due to a power failure.