# Amps-variable speed blower motor



## Lhoward145

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


----------



## Vaporx

There is no low, medium or high for variable speed...It's "variable speed". :thumbsup: _*X13*_ motors have speed taps, for different static requirements (your supposed to check static to determine speed requirement). I would think the only concern is staying below max rated amperage.


----------



## Vaporx

_*..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.:icon_cheesygrin:


----------



## Hugo Jass

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.


----------



## beenthere

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.


----------



## sglobe

Lhoward145 said:


> 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


well here's what i have found about this *Amps-variable speed blower motor, *there's this 12 amp Variable-Speed Electric Blower i don't know if this is what you are talking about. hope this helps.


----------

