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jakethebt
12-08-2006, 08:10 PM
When I moved in to my house, the guy left two old industrial heaters. After a few years I decided to install them in my garage, only to find that they were 480v three phase industrial heaters. It was now clear why they were left behind. The heater coils were running at 480v while the electric motor was stepped down to 220v. I just bypassed the converter and re-wired the coils to run on 220v. They put out less heat, but still work.

Now the problem... last winter one of the motors went bad. No problem, one still did the job. Now, this week the other decided to stop working too.

They appear to use capacitor start electric motors and from what I can tell, the capacitors have popped/exploded. There is oil residue on the top and the motors will not start.

The questions...
1. Why did they explode? I have noticed that they seem to run for a long time with the reduced voltage. Possibly a few hours. Maybe the motors were not rated for that long of a duty cycle? Perhaps it was just their time?

2. Is it feasible to have them rebuilt? I have been pricing them out from Grainger... ouch close to $200 each.

JimN
12-08-2006, 08:17 PM
Hard to say from here why they exploded but don't touch or handle the oil until you find out what it is. Dioxin was used for years in things like that and it's extremely toxic.

You should be able to have just about any motor rebuilt, look in the yellow pages. They may also have some rebuilt motors that would be better suited for your heaters, too. There are a lot of sources for motors.

Chief
12-08-2006, 09:02 PM
Hard to say from here why they exploded but don't touch or handle the oil until you find out what it is. Dioxin was used for years in things like that and it's extremely toxic.

You should be able to have just about any motor rebuilt, look in the yellow pages. They may also have some rebuilt motors that would be better suited for your heaters, too. There are a lot of sources for motors.

As Jim said DO NOT come in contact with oil by touch or sticking your nose up to smell. Some motors have PCB's in them. See below:

PCB's are a class of chemicals known as polychlorinated biphenyls. They are entirely man-made and do not occur naturally. They were first manufactured commercially in 1929 by Monsanto, their sole U.S. manufacturer. They were used in many different types of products including hydraulic fluid, casting wax, pigments, carbonless copy paper, plasticizer, vacuum pumps, compressors, heat transfer systems and others. Their primary use, however, was as a dielectric fluid in electrical equipment. Because of their stability and resistance to thermal breakdown as well as their insulating properties they were the fluid of choice for transformers and capacitors. As a matter of fact, because of their fire resistance, they were required by some fire codes.
During the 1970's, the health risks associated with PCB's became a major consideration due to several well publicized incidents. The most noted of these is known as the Yusho Incident. It took place in Japan when a rice oil plant had an equipment leak of PCB fluid into the product. The rice oil was sold and consumed resulting in many people being adversely affected.
Among the health affects of PCB's are skin ailments called chloracne, reproductive disorders, liver disease and neurological problems in children. PCB's are a suspected human carcinogen and a known animal carcinogen. They are resistant to degradation and therefore persist for many years in the environment. Furthermore, they bioaccumulate in the foodchain and are stored in the body fat of animals and humans. Because of the health and environmental risks associated with PCB's, an Act of Congress, the Toxic Substances Control Act of 1976, directed the U.S. Environmental Protection Agency (EPA) to ban the manufacture of PCB's and regulated their use and disposal. EPA accomplished this by the issuance of regulation in 1978. The State of Connecticut, however, banned the manufacture of PCB's and began regulating them effective July 1, 1976. Both EPA and Connecticut, although banning their manufacture, allowed equipment containing PCB's to continue in use for the remainder of their useful lives.

JimN
12-08-2006, 09:46 PM
Thanks for the correction. Dioxin is in Agent Orange, not motors.