You'll get a different amp draw when the panel is open -- it should be closed to get proper reading.
How do you figure what the proper range is for amperage on an indoor blower motor?
For example: Let's say the FLA for the indoor blower motor is 4.8. Generally, how many amps should you be pulling? And is it ok to take the amp reading before the capacitor? (because the capacitor is in the blower compartment on the particular unit I'm thinking of and I need the panel on to get proper amps).
You'll get a different amp draw when the panel is open -- it should be closed to get proper reading.
I appreciate your response. However I already knew that. That's what I said. What I need to know is how to figure what amps you should be getting based on the FLA of the indoor blower motor... ?
Well at 4.8FLA, obviously you have to see amperage below that or there is something wrong with it. As far as any kind of formula or figure on what it would normally pull, I don't think there is any definitive answer, because amperage can vary depending on weight, density, and moisture content of the air as these all affect the actual load on the motor. Maybe somebody here can help a little more with that. Also I take amperage of any single phase motor on the common wire.
General rule of thumb is 75%-90% of FLA is typical on the blower's high speed. The manufacturer can give you a better idea, but you will need the static pressure measurement of the return duct and the supply duct. Find that pressure on the fan curve and your proper amp draw should be indicated.
Manufacturers often use the same motor on several sizes of unit so you really need to check w them.
Great info! thanks bob_scheel.