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#1 |
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Junior Member
Trade: installation
Join Date: Nov 2011
Posts: 1
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Amps-variable speed blower motor
Carrier model 58MVC. What are amps pulled for low, medium, and high speeds for variable speed blower motor? Have checked all install materials and on-line web site. Thanks
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#2 |
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Member
Trade: residential service
Join Date: Jun 2011
Posts: 33
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Re: Amps-variable speed blower motor
There is no low, medium or high for variable speed...It's "variable speed".
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#3 |
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Member
Trade: residential service
Join Date: Jun 2011
Posts: 33
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Re: Amps-variable speed blower motor
..and if you're trying to compare speed "control" of multi-speed PSC motors to ECM motors...there's no comparison.
True speed control for AC motors is via motor "poles"...6 pole-1200, 8 pole-900 etc. Most multi-speed PSC motors are 6 pole (1200 rpm) and have the run winding "tapped" at differ locations, effectively reducing the horsepower, which when under load, reduces the speed. ECM motors are DC motors with permanent magnet rotors...variations in speed are accomplished by changing the field voltage, which is what the controllers do. Even then, the controllers "see" power relative to some CFM value. Drops in power are translated as reductions in airflow, so the motor increases in speed to maintain the power/air volume. ..sumpin' like that. |
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#4 |
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Name says it all
Trade: Trainer
Join Date: Apr 2011
Posts: 5
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Re: Amps-variable speed blower motor
Air movement is mass flow.
Mass flow is work. Work requires energy. More work more energy. PSC motor higher static less work less energy lower amp draw. ECM constant torque higher static will maintain torque (amps). ECM constant CFM ( almost allways incorrectly called variable speed and if we really want to be picky, it's pounds of air not boxes as in CFM) higher static faster rpm more work to try to maintain CFM higher amp draw. ECM constant CFM low static lower work less amps.
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#5 |
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Senior Member
Trade: Service/Installation
Join Date: May 2009
Posts: 600
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Re: Amps-variable speed blower motor
The amp draw of a VS ECM will vary with how hard the motor is working to move its set CFM.
At .4 static moving 1200 CFM it will be low. At .8 static moving 1200 CFM it will be high. Same amount of air, but different amounts of work to move the air.
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#6 | |
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Junior Member
Trade: mechanic
Join Date: Jan 2012
Posts: 1
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Re: Amps-variable speed blower motorQuote:
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