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RK05 fan blower motor

A

anders_bzn

Experienced Member
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Jan 27, 2016
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263
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Sweden
I'm restoring a RK05 drive, but have a problem with the fan. It rotates, but really slow. The motor capacitor is fine. The motor gets crazy hot, over 100 degrees Celsius within minutes. I have opened up the motor and its has at least one burned winding.

The fan assembly is this one: https://www.tedss.com/2031000546

Where can I get a new motor?
 
Kooltronic is still very much in business, so they'd be the first place to try for a replacement.

However, if you have a motor shop in your area, there might be a more economical alternative--have them rewind the field coils. For larger motors, it's quite a business...
 
Well, I noticed that Kooltronic was still in business. I guess your right, finding someone that can rewind the motor is probably the best. I have threaded a broken core memory so maybe this is doable. On the other hand, there are people out there that can rewind a motor but probably on one that makes their living on fixing core memories.
 
Before you think about rewind, you could look at the bearings. Many times the fan and or motor bearings are either worn or just plugged with dust and dirt. It may be worthwhile to attempt some disassemble and cleaning. Even if you can not get the bearings out, maybe a little lube sprayed in the right places may loosen up the whole thing. My bet is the fan bearings, Mike
 
The motor turned very nice and easy!

rk05-fan-motor-2.jpg

You can see the black in the middle of the picture, this is a burned winding.
 
Mike_Z said:
Before you think about rewind, you could look at the bearings. Many times the fan and or motor bearings are either worn or just plugged with dust and dirt. It may be worthwhile to attempt some disassemble and cleaning. Even if you can not get the bearings out, maybe a little lube sprayed in the right places may loosen up the whole thing. My bet is the fan bearings, Mike
Click to expand...

Yeah, dried-out "olite" bearings. But that's not his problem.
 
The black in the middle of the picture is discolored fish paper that is used for insulation between the winding and the slot. The winding under the fish paper (it's not really paper, but something like an oil cloth), must have shorted, resulting in shorted windings. A shorted winding will have many times full load current in it and will get hot. If you cut thru the paper you may get a glimpse of the burnt windings. How does the end turns of that coil look? They should not be wrapped. Also look at the other side of the winding. This side is in the bottom of the slot. The opposite side should be in the top of the slot, maybe 4 or so slots over. They should also show signs of heating. Have you checked resistance between the winding and the core?

Either way, a different motor or a rewind is in order. Having the motor rewind is a real option. At the power plant we rewound the small motors 50hp and less and shipped out the larger ones. Mike
 
Found a motor shop very close to me, In the same village that I live. I'll go and visit then on Monday morning and see what they say about it!
 
Visited the local motor shop today. They wanted about $330 for a rewind of the motor. I have to think about that for a while. Or come up with another motor to retro fit on the fan housing.
 
Sent a mail to Kooltronic and asked for parts to the KBB33, they informed me that it was EOL (Which I already knew) and that they didn't have any spare parts for it. It was worth a try.
 
Have you thought about rewinding it yourself? I used to rewind and balance the armatures of small motors for electric model aircraft and cars many years ago, it's not that difficult. And these days there is Youtube to help with 'rewind electric motor' having dozens of hits. Start with measuring the wire thickness with a micrometer or digital caliper to find the AWG/SWG, price a spool of coated wire and go from there.
 
There may have been substitute blower models from Dayton or other manufacturers, and some of them may have cross-reference pages. For instance this one seems about the right size, slightly faster but 3x current draw. With a bit of searching you may find something closer to the KBB33 or perhaps put a recurring search on eBay for that model as there are a few Kooltronics of various sizes listed there.
https://www.ebay.com/itm/Centrifuga...ton-4C005-4C446-1TDP7-Fasco-A166/302153379763
 
1944GPW said:
There may have been substitute blower models from Dayton or other manufacturers, and some of them may have cross-reference pages. For instance this one seems about the right size, slightly faster but 3x current draw. With a bit of searching you may find something closer to the KBB33 or perhaps put a recurring search on eBay for that model as there are a few Kooltronics of various sizes listed there.
https://www.ebay.com/itm/Centrifuga...ton-4C005-4C446-1TDP7-Fasco-A166/302153379763
Click to expand...

I looked at this one. It's just a little bit to big.

Anyway, I might have found a motor. I will change it for some S-modules...
 
anders_bzn said:
I looked at this one. It's just a little bit to big.

Anyway, I might have found a motor. I will change it for some S-modules...
Click to expand...

Have a motor on it's way! Tested, but the bearings sounded bad. So I ordered some new 608-2RSL SKF (yes Swedish quality) as replacement.
 
As a separate project we should determine why the blower motors are going bad. I have three of them where the internal connection between the start coil (black), run coil (blue) and green wire has the run coil disconnected.
 
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