Created Date: December 17,2013

Created by: Tinker

Yes, the frame size I got from a spec sheet is 48Z. It also said mount F1.

Big Brother, err, I mean, Google, is your friend

Top of the search results for 48z frame is a page that in turn links to This

If you had been looking at Ironhorse (tm) motors you will be in for a bit of sticker shock, but you can hope you get what you pay for.

At 1200 rpm nominal you won't have to slow it down too much for full flow. Which is good since below reated speed a motor will be constant torque at best (diminishing horsepower), slowing a 1750 rpm motor to 900 (about half speed) will put you well below 1/2hp and the motor could well be overloaded at trying to repalce the original 900rmp 1/2 hp. The problem won't be quite so bad going from 1200 to 900 (3/4 speed).

If this motor is soo hard to get at I wouldn't think you'd be wanting to maintain brushes on a brushed DC motor and I can't see where a brushless "DC " motor would have much advantage over an induction motor for running an attic fan.

Created Date: December 17,2013

Created by: alternety

Thanks tinker. I sure wish I could get a data sheet like the one for that motor for the motor I need. The only answer that will actually work is from someone who actually knows what the shaft on the current motor is. Such people have to be scarce, but low probability things happen.

Google is my friend, as well as several phone calls to manufacturers and distributors. They will not share.

Worst case, I take the thing apart and have to put it back together without accomplishing what I want if I can't make the squirrel cage fit the motor when it is mounted. Then I can measure the shaft and determine the shape and hunt for a motor or a way to adapt it. There are real limits to what can be done to the shaft with a hacksaw and a drill. The maintenance of absolutely straight when fixing it would be a bear unless it is smaller than an available shaft profile. If it is possible to fix, I can take it to a machine shop for work.

Brushless DC would be a nice low maintenance solution, but I suspect the initial set of brushes in a "regular " DC motor would probably last longer than I will. My water pump is brushed and after 8 years of supplying all our water, no significant wear on the brushes. But you are indeed correct in saying I would not want to replace brushes. To do that I would have to take the motor out.

Created Date: December 16,2013

Created by: alternety

I am trying to rework a 110VAC 1/2 HP induction motor fan assembly to use 220VAC 3 Phase VFC. I need feedback controlled speed.

My problem is trying to find a physical and speed match to the current 110VAC single phase motor. It is direct coupled to a squirrel cage blower. It turns out the motor is a special build for the fan assembly manufacturer. It runs at 900 RPM.

It is a Marathon motor 48A8011002 (or 48A8o11002 I am not sure about the character after the second 8). Full part number is W48A8011002-A. It is sold by Mimco Eqpt as part number 8395. But none of the above sources is able to provide physical measurements so I can try to find a match. Marathon does not list that part number because it is a special order for the customer.

I am trying to avoid taking the existing motor out to make measurements. It is in the attic, access from one side only, and very very hard to remove. I did it once because of a bad install by the experts. And that was before you had to lay in 2 ' of fiberglass. If I take it out and can't replace it I then have to put it back. Which is much harder.

I believe the motor may have a special shaft. If that is true, I could possibly make some sort of adapter. But the basic size and mounting could be tricky. I could probably make a base adapter if the stars are in the right configuration.

It seems possible to get a bit larger motor at 1750 RPM and use the VFC to keep it centered at 900 RPM.

Does anyone know what motor I can use to physically replace the existing motor?

Existing - 120VAC, single phase, induction, 1/2 HP, 900 RPM

Needed - 220VAC, 3 phase, 1/2HP (maybe a little larger), VFC rated, 900 RPM.

A potential alternative is a DC motor. But I have 120VAC available and I would need a transformer to feed a high voltage DC motor controller. I actually rather like permanent magnet DC motors. The pressure pump for my house uses one.

Suggestions of alternatives welcomed.