Meaning of "Max Unbalanced Load Capacity" On Small Generator Nameplate
Meaning of "Max Unbalanced Load Capacity" On Small Generator Nameplate
(OP)
I have seen many small 1ph standby gensets with a max unbalanced load capacity figure on the nameplate.
Usually this number is given as 50%.
Some larger ones have a rating of 25% or even 10%.
I am not sure how exactly to apply this number. 10% at what point in the calculation?
Usually this number is given as 50%.
Some larger ones have a rating of 25% or even 10%.
I am not sure how exactly to apply this number. 10% at what point in the calculation?





RE: Meaning of "Max Unbalanced Load Capacity" On Small Generator Nameplate
A generator may have a 50% voltage drop under load. That's why we use Automatic Voltage Regulators. The AVR increases the excitation current to compensate for the voltage drop under load. The AVR sees the total voltage (240 Volts). If a heavy load on one 120 Volt winding causes that voltage to drop to 60 Volts, the AVR will see, initially, 180 Volts. It will increase the excitation about 33%.
Now the voltages across the 120 Volt windings will be 60 V x 133% = 80 Volts, and 120 Volts x 133% = 160 Volts.
Unacceptable.
In the real world, non-linearities including saturation will probably affect these simple calculations, but you get the point.
Bill
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"Why not the best?"
Jimmy Carter
RE: Meaning of "Max Unbalanced Load Capacity" On Small Generator Nameplate
RE: Meaning of "Max Unbalanced Load Capacity" On Small Generator Nameplate
Keith Cress
kcress - http://www.flaminsystems.com
RE: Meaning of "Max Unbalanced Load Capacity" On Small Generator Nameplate
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