Wiring Polarity Question

[JoshP]

As I indicated in a previous post, my electric fan is dead; today, I exchanged it for a new unit. I'm installing the fan as a puller, which means that with this fan I'll need to turn over the fan blades and also reverse the polarity of the wires.

When I installed the previous fan, I simply hooked the default positive (blue) wire to ground and the default negative (black) to power to do the polarity reversal. The fan worked well for two days, and then the fan unceremoniously died.

I determined that it was probable brush failure in the electric motor (fan would just barely turn, and squealed whilst doing so) after doing some tests.

Here's my question: did I do the polarity reversal correctly in my previous install, or do I need to do a 'flash' like one would when converting the polarity of, say, a generator? I'm quite open to the possibility that I just had a bum fan /ubbthreads/images/graemlins/tongue.gif.

I know that this is a simple (possibly even dumb) question, but it's something that has me a little paranoid. Guess I just need a little assurance. I don't want to have to take this fan back again b/c of a mistake on my part. Help?

 

[kennypinkerton]

DC electric motors are "timed" to run in one direction, and will not last long running in reverse - brush arcing and excess heat buildup is what you get when you run them backwords - both of those are brush and winding killers. Buy a puller setup if that's what your going for.

 

[JoshP]

This fan was shipped as a pusher fan, but the documentation that comes with the fan says that it can be converted to a puller by removing and turning the blades over, then reversing the wire polarity.

I interpreted this as hooking the default positive (blue) to ground and the default negative (black) to hot.

 

[kennypinkerton]

Probably right on the wiring... But like I said "most" motors come timed to run efficiently in one direction. There are nuetrally timed (reversible) motors too - you'rs sound like it might be, but if'n it's a cheap chinese part, buy a better one already setup for running the way you need it to.

Personally, I'd take the one you have back to wherever you got it and get a refund.

 

[JoshP]

This one's a Hayden 3680, like the one I had, but it seems to be a newer (or at least, slightly redesigned) version. I'll give it another chance and see what happens. S**t can happen sometimes; this one's made in US from it's labeling.

FWIW, when it was working, it kept everything nice and cool.

 

[kennypinkerton]

2 questions... Is it wired to the stock thermosensor?
If yes or no... Are the wires getting electicity right now? (could be a bad thermostat, or just a bad wiring connection down the line somewhere, or even an old fuse that wasn't rated for the new fan motor)

Just a couple of other things to check before you return it. electric motors are pretty tough things - there's lots more along the circuit that are more fragile.

 

[JoshP]

Way ahead of ya Kenny /ubbthreads/images/graemlins/tongue.gif. When the car first started showing overheating symptoms, I pulled off the road and into my shop. Borrowed a test light and went to work.

Checked fuses: good. I tested the green circuit which was still getting power. I bypassed the thermal switch (one I bought with the fan, an adjustable unit) and connected the fan to straight power. I also tried to use a different grounding point (had been using the bracket for the thermal switch, bare metal...went to a bare metal bolt on the thermostat housing). None of these gave me any results.

I asked my mech about the issue, and we did manage to get the fan to spin, albeit very slowly and with a fair amount of squeal. He said that the brushes or bearings had probably gone bad in it. So, I returned the fan to Advance and they gave me a new one.

 

[kennypinkerton]

the second one died too? get a different brand! That mfger is having seriuos quality control problems in the batch of fans that your getting if you've gotten 2 and they've both died.

 

[JoshP]

The fuses are the stock 17/35 fuses, all good. I had the fan connected to the green wire that originally connected to the green/black which supplied the original fans. Those two original fans would draw more current than the aftermarket (I believe the draw is around 8 amps for the aftermarket, don't quote me on that though).

 

[kennypinkerton]

I think your right on the current draw.

 

[JoshP]

No, no, no...I must've misstepped. I have the second one that I received in exchanged for the first one that died. I haven't installed the second one yet.

I was asking these questions before I did this installation just to make sure I have my procedure correct.

The above posts speak of my experiences with the first fan. I haven't installed the second one yet.

 

[kennypinkerton]

Oh, OK. install the second one... If the instructions say "reverse the polarity", that means wire it backwords - like you did. When you get it in, doublecheck the rotation of the fan, and make sure it's going the way it should.

If this one only lasts a few days... Get your moneyback, and buy some other brand - even if you gotta go somewhere else to get it.

Yes, it is possible to get a bad motor from the store.

 

[JoshP]

Yeah...I can pretty well agree that sometimes a store can inadvertently sell a bum product from time to time. The important thing is what they do to make it right again. The old fan might've been sitting on the shelf, been dropped or just got old. Or it could've been a bad unit straight from factory.

Anyway, I'll give this one a shot...if it dies on me, then I'll look elsewhere (possibly PermaCool).

 

[PAUL161]

Josh, The best place I know to get electric fans is through Peyton Performance in Texas. www.peytonperformance.com . They not only sell a very good product, Flex-A-Lite fans, but are also willing to help you in making a decision of what type to use. They also have competitive rates. Nice people! /ubbthreads/images/graemlins/thumbsup.gif /ubbthreads/images/graemlins/thumbsup.gif PJ