Blower motor specifications


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Old 09-04-08, 04:56 PM
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Blower motor specifications

I have a 5 ton roof mounted HVAC unit here in Arizona. This is actually a commercial unit since I am one of the lucky ones who has 3-phase running to the house. I was out of town last year and my blower motor went bad and had a tech replace it. This year, my bills are $100-200 more per month. I thought that he stated that I had a 3-phase blower but it was not in stock and he could replace it with a single phase motor. The spec on the unit is 230-1-60 for the blower (3-phase for the compressor and single phase for the OD fan).

First of all, is there a 3-phase blower? I only seem to see single phase. Next, the motor that is in there now is a 3/4 HP, but the spec is for a 1 HP. Could the wrong size motor drive my bill up that much or is it a combination of a too small motor with a different phase setup.

Thanks in advance...
 
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Old 09-05-08, 12:40 PM
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I don't know how you would wire a single phase motor into a three phase system. The contactor should be a 3 pole and I don't think the voltages between any 2 of the phases would be suitable (not to mention the uglyness of a load that inbalanced). A 3/4 hp motor on a fan rated for 1 hp is a real bad idea. I know, I tried something similar a couple of weeks ago and killed the motor in about 10 days. I think you need a new tech.
 
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Old 09-05-08, 05:12 PM
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And don't forget moto, the rates went up. Mine increased about 20% when I go over hmmm 1400Kwh/mo?....I'm sure you couldn't since they bombarded us with notices
 
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Old 09-05-08, 06:15 PM
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I am on SRP, and I think our rates went up about 12-13% (APS was even more), but I am at about a 30-35% increase in my overall bill. I still think that the motor is mostly to blame.

I spoke with a regional rep from the company that sold my unit. There are no 3-phase blowers, only single phase. I did find my old paperwork and it stated that the tech replaced the variable speed motor with a "standard" motor.

Anyone know how a variable speed vs. "standard" would affect my HVAC system? I can also see the 3/4 HP motor working harder and longer than a 1 HP. I did have to replace the start capacitor earlier this year (motor would not start unless I spun it to get it going). I did run the blower continuously for about 3 weeks until I could get the cap and the bill went up by $145. Maybe the windings got a little burnt with the bad cap (the motor would turn slowly until it would overheat and stop).
 
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Old 09-05-08, 06:21 PM
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What is the make, model, serial numbers of the unit in question?

Most Rooftop 460 volt 3 phase units have a single phase 460 volt cond fan motor.

As for your blower, you had a variable speed replaced with a standard motor?

The control logic if there must be going nuts!

Your system has been butchered and is much less efficient than designed.
 
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Old 09-06-08, 02:34 PM
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Make and model: BAUH T060AB, serial NALM008139. It is about 6 years old. (I think it might be a Coleman w/o the name tag).
 
 

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