53MY benny room heat

[MikeP]

Not willing to leave a "puzzle" alone, I pulled one of the hot motors and the cool motor to see if there was any internal difference that I could see - thinking maybe there were some differences in the spacers used internally for the armature on each end that might cause excessive friction but they were the same and both motors "spin" equally well when turned by hand. BUT...the hot motor's coils had 1/2 the resistance of the cool motor's coils. The hot motor's coils had approx .8 Ohm resistance and the cool motor was nearly 2 Ohms. I have no idea what the resistance should be.

Also, the hot motor's windings were soot-colored while the cool motors windings were normal copper color. So clearly the hot motors are too hot...but why?

 

[davidwigler]

Could the hot one be wound for 24 or 12 volts?

 

[MikeP]

It was my thought as well but all three are clearly stamped with the motor number and "32V"

 

[MikeP]

BUT...I just realized that the cooler motor, though visually identical, has a different part number than the other two SO...I'm assuming that the cooler motor is a continuous duty motor while the other two are not.

I did a bunch of research and have found that sourcing 32V blower motors is not a problem - Jabsco makes them - however, none of their 32's are constant duty. They do have 12/24VDC and 115VAC constant duty flange-mount blowers that are externally identical and bolt in place of the existing blowers. So I'm considering purchasing either a 12V or 115V blower for the Gen area. I would want it to be controlled exactly as the current blower is so some rewiring would be necessary to get the correct voltage - 12 or 115 - to the blower as opposed to the 32V that is there now. The 115V blowers are not ignition protected but the 12/24s are. I tend to think that since the batteries (hydrogen) are in the Gen room, ignition protected is a good idea which would mean 12V.

 

[MikeP]

Here's a pic of the two motors the hot one (200F) on the left, cool one (140F) on the right. Both drew 1.8A at 34V. Seems apparent to me by the color of the windings that the hot one is not designed to run for extended periods...

 

[bobk]

The armature varnish on the hot one looks like it is really shot. The housing also looks duller.... older or just from the heat? I think you are smart to replace it before it gets to be a problem.

Bobk

 

[AL BAUMER]

Did you run that blower full time when the Gen was operating or only after shutdown? Seems like a good idea and one I am considering. The PO of our boat had installed 120vac engine room blowers that they turned on when the mains were shut down for the day to reduce ER temps. They pretty much ran the Gen 24/7 when they left the dock but I don't know if they operated the oem gen room blower or not. They did not install any additional blowers in the Gen area.

Yes we ran the blower while the gen was operating

 

[davidwigler]

I wonder if a good alternator shop could rebuild it as continuous duty, maybe better than new?