Motor strapping HV-LV

[ActionDave]

GD, here's my guess.

I don't think it worked consistently. It just ran. Since the motor was wired HV the overall amps were less so the effects of single phasing were not as harsh. Like you said the slightest kick would get the motor spinning.

 

[Open Neutral]

Congratulations! Unfortunately you have left us (and the Wisconsin Tourist Federation) wondering why it ran any better or more consistently when set up for HV mode!!

There has to be a clue in there somewhere related to the (apparent) fact that it started consistently when bumped with either one of the LV winding sets connected, but sat and vibrated with both connected. I will not be able to sleep tonight till somebody figures that one out. (Or until my bedtime, whichever comes first.)

First, I was testing it unloaded. Granted a belt-driven fan is not a lot of starting load, but it is some drag.
Second, when I hooked both winding up, unloaded, it did start. That seems to have been a "Yea, all three this time just to screw with him..." move by the breaker. A subsequent attempt also started but in single-phase mode.

That still does not give me a clue why it worked consistently with the series setup, unless somehow the extra inductance or the lower current affected the behavior of the defective breaker itself.

My Guess: Crap shoot; the breaker excited all three phases that time.

 

[GoldDigger]

My Guess: Crap shoot; the breaker excited all three phases that time.

BTW, I think at this point you have a good idea why the original motor failed too. :happyyes:

 

[Open Neutral]

BTW, I think at this point you have a good idea why the original motor failed too.

Yes.... But they don't last more than 3-4 years anyhow, he told me. This one is rated for max of 40C; I hope it stays that cool but won't make bets on it. Glass shops are HOT....

We discussed finding a starter contactor so we can an add a lost-phase detector.

 

[kwired]

Yes.... But they don't last more than 3-4 years anyhow, he told me. This one is rated for max of 40C; I hope it stays that cool but won't make bets on it. Glass shops are HOT....

We discussed finding a starter contactor so we can an add a lost-phase detector.

sounds like there is a need for a different design of fan where the motor is not in the airstream.

 

[Smart $]

sounds like there is a need for a different design of fan where the motor is not in the airstream.

Probably not just out of the airstream, but also outside. I imagine the nearby air inside is just as hot.

 

[kwired]

Probably not just out of the airstream, but also outside. I imagine the nearby air inside is just as hot.

true.

 

[Open Neutral]

This is a rectangular cupola about 3' x 3'; it replaces a skylight bubble.

The fan fills the opening at roof level; the motor is mounted vertically above it, driving the vertical shaft via dual pulleys.

 

[kwired]

This is a rectangular cupola about 3' x 3'; it replaces a skylight bubble.

The fan fills the opening at roof level; the motor is mounted vertically above it, driving the vertical shaft via dual pulleys.

If motor is not in airstream, and is that close to outdoors maybe you can also ventilate the motor compartment somehow to help keep motor temp lower.

 

[Open Neutral]

If motor is not in airstream, and is that close to outdoors maybe you can also ventilate the motor compartment somehow to help keep motor temp lower.

It is directly in the airstream, within the fan blade radius.

 

[kwired]

It is directly in the airstream, within the fan blade radius.

There goes that theory. When you said it was a belt driven fan I thought there was a good chance the motor maybe wasn't in the airstream.