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Renewable Energy Q&A / Re: Max winding temp
« Last post by Pete on April 24, 2022, 05:12:37 pm »Hi LH, hopefully lowering the frequency will sort it out. Of course it will run slower but hopefully not so hot.
My understanding is that the frequency needs to be lowered when the voltage is lowered otherwise the motor will draw more current as the frequency falls.
Inductive Reactance XL =2 x pi x F x L
So pi doesn't change 3.14 is a constant
F is the frequency so if it is lowered then
L inductance stays the same but
XL inductive reactance will fall, which means that the motor will draw more current, hence dropping the voltage compensates for the lower inductive reactance.
I have not had a real lot to do with VFDs over the years, I did my apprentiship as a motor rewinder. VFDs were not very common then.
Good luck
Pete
My understanding is that the frequency needs to be lowered when the voltage is lowered otherwise the motor will draw more current as the frequency falls.
Inductive Reactance XL =2 x pi x F x L
So pi doesn't change 3.14 is a constant
F is the frequency so if it is lowered then
L inductance stays the same but
XL inductive reactance will fall, which means that the motor will draw more current, hence dropping the voltage compensates for the lower inductive reactance.
I have not had a real lot to do with VFDs over the years, I did my apprentiship as a motor rewinder. VFDs were not very common then.
Good luck
Pete