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(08-14-2018, 11:42 AM)RPE1 Wrote: I have two vent hood blowers I got out of a commercial kitchen years ago. They each have two squirrel cages with the motor in the middle. They are in a housing with a transitional duct that turns rectangular. They move alot of air. And I mean alot. I put them in the back of the shop in front of a window and blow shaded air through the shop out the front.
The motors are GE. They are 3 amp. I put a meter on them yesterday and they were pulling 2.3 or so. I stopped and started one and it jumped up to 3 amps and then back to 2.3 or so.
After the motors run, they are very warm. I don't know why. Is it normal for them to be very warm? I can stick my finger through the housing and touch the motor and it's hot after it runs a while.
The cords are not warm. They are on a 20amp circuit. They are the only thing on that circuit.
Is there any thing I can or should do?
Thanks
RP
Today I tried blocking both ends of the blowers. With out blocking they were running steady at 2.1 amps. With partial blocking it dropped to 2.0 and a large decrease in airflow. I totally blocked both ends and it stayed at 2.0 amps.
I freed both ends and it went up to 2.1 amps.
I don't think there is much advantage to blocking the air inlet. I even tried blocking the exit duct. It didn't change appreciably.
So I'd rather have the airflow and if I burn them up, I burn them up. It 102 or so here. I need the breeze.
Unless someone has any other things to try, I'm letting them run wide open.
RP
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(08-24-2018, 08:05 PM)RPE1 Wrote: Today I tried blocking both ends of the blowers. With out blocking they were running steady at 2.1 amps. With partial blocking it dropped to 2.0 and a large decrease in airflow. I totally blocked both ends and it stayed at 2.0 amps.
I freed both ends and it went up to 2.1 amps.
I don't think there is much advantage to blocking the air inlet. I even tried blocking the exit duct. It didn't change appreciably.
So I'd rather have the airflow and if I burn them up, I burn them up. It 102 or so here. I need the breeze.
Unless someone has any other things to try, I'm letting them run wide open.
RP
You are running well under the 3 amp full load current on the name plate. I think it will be fine. It may seem hot to you but not to the motor. Roly
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It sounds like a shaded-pole motor, like what's used in table fans and range hoods and such. They don't change current draw very much with changes in load, even when stalled. Induction motors, on the other hand, have locked rotor (starting) current typically around 4-8 times rated current, dropping rapidly as it nears rated load, and changes in load within the normal 0-100% load range are very visible on an ammeter.
Too hot to touch is perfectly normal for most motors, and hot enough to burn you is not unusual for some types. That's nothing to worry about as long as the current is below the nameplate value.
Tom
“This place smells like that odd combination of flop sweat, hopelessness, aaaand feet"
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(08-25-2018, 07:24 AM)TDKPE Wrote: It sounds like a shaded-pole motor, like what's used in table fans and range hoods and such. They don't change current draw very much with changes in load, even when stalled. Induction motors, on the other hand, have locked rotor (starting) current typically around 4-8 times rated current, dropping rapidly as it nears rated load, and changes in load within the normal 0-100% load range are very visible on an ammeter.
Too hot to touch is perfectly normal for most motors, and hot enough to burn you is not unusual for some types. That's nothing to worry about as long as the current is below the nameplate value.
Thanks for all your replies
RP
