Cruisair air handler blowers- If one ceases to turn...

Anyone with a boat and or house would do well to buy a meter that can check caps. I've got a Fluke 115 which was around 150 bucks. My neighbors and buds know I have it and that feature is used often. Amazing how many things have caps, and amazing how often they poop.

I even keep a box of random caps, sometimes you find one that is close that keeps you going til you get the right one. Anytime a machine heads for the dump and it has caps, the caps get ripped out, tested and thrown into the box.

one was six years before I sold the boat. The present one is six months and running great.

RT Firefly said:

Greetings,
Mr. C. My non resident alien suggests it may be a bad centrifugal start switch and I quote...


"The OP said his unit has a "run" capacitor, replaced and still not start ... if it runs fine after being turned by hand then it is probably a bad centrifugal start switch inside the end bell of the motor.

It is closed when at rest and on powerup it supplies power to a starting winding. Once up to a certain speed it opens and the motor runs normally. That is why starting by hand works.

If it just hums when power is applied, and then accelerates after a push, listen for the noise of the switch operating, it is a whirr followed by a soft click."

Click to expand...

It would be a surprised if that small motor has a start winding. The centrifugal switch means their is a start and a run winding. Little blower motors do not need a lot of starting torque.
My drier, well pump, air compressor, Jabsco utility pump all have start windings with centrifugal switch.
My furnace blower motors do not.

Greetings,
I haven't got a clue WHAT the problem could be but it has also been suggested that the OP...

"Going to the Dayton website with the motor ID will get him a circuit diagram then he will know what he has rather than spend another 30 posts jousting with amateur electricians.

The starting winding is out of the circuit when the motor is up to speed. It most certainly will run as that is the normal operating condition. It is only in circuit when starting ... that is why is it called a "starting" winding.

Maybe suggest he Google electric motor centrifugal start switch circuit."

If the motor has 3 wires, it probably has a start winding, If it has 2 wires, then it doesn't (unless the start capacitor is inside the motor housing). In which case it would possibly have a centrifugal start switch. (do not count the ground wire).

Most fan motors do not have a centrifugal switch controlling the start winding. They do have a start winding fed through a capacitor that shifts the phase a bit to get some starting torque. No expert here on exactly how they are set up, but they certainly have no switch.

Motors that need good starting torque do use the centrifugal switch, and some use capacitors too.

Braved some high winds and cold (cold for here anyway) on the open flybridge to install the new cap today. It worked ! Also interesting is there is no perceptible play in the bearings of either blower... I mean zero (from feel anyway) I mention this because that would make the "stopping in a dead zone, thus not starting the next cycle" theory highly unlikely in this case.

Having said that, the blowers, when off, don't turn quite as "spin forever-ish" as they did this spring (the last time a blower stopped turning....(not this one, it's twin on the other side of the dual air handler box). I hope that is because what little oil is in there is slightly thicker in the colder temps.

And there appears to be no way to oil the bearings...the motor end is sealed and the blower/arbor end impossible to get to. Oh well.

So, works again for now....but we'll see how long it lasts.

Greetings,
Mr. C. Glad you're back in business. One technique for oiling those capped/sealed end bearings is to drill a small (1/16") hole just offset a touch from the end "dimple". Oil can then be added as necessary. The arbor end might be reached with one of those red tubes that comes with every WD40 can (and promptly disappears with the first use). I have had occasion to join two together with heat shrink tubing for "extension/remote" oiling. Hold onto that sucker for sure.

NOT suggesting you use WD for lubrication but there ARE aerosol lubricants with that elusive red tube.

Further...the bearings are most likely Oilite and should not need lubrication but they do dry out and I've extended the life of several motors by oiling.

Happy ending!

RT Firefly said:

The arbor end might be reached with one of those red tubes that comes with every WD40 can (and promptly disappears with the first use).

Click to expand...

So true about the red tubes....one would think by 2016 they would have figured out a better method of storing the things than Scotch tape on the can. I suppose a couple of rubber bands (or one wide one) around the can might do the trick but never occurs to me to buy any.

WD40 is not a lubricant, sort of.
I have oiled motor shafts using full synthetic engine oils.
Advantage of synthetic is they do not burn-oxidize, dry up, so they last.
I would use a 5w-20 and drip it off a long tool-wire onto the shaft net to the bushing,

I found out about using synthetic oils on motors on computer fans. The fan bearings eventually dry up, even relubing with dino oils. But using synthetic oils, the fans don't dry up, I have years of proof that shows me this. Since then also other fan motors I have fixed using 100% synthetic oil.
There is friction in a bearing, even if it seems there is none. And over the long long time, regular greases - oils do a slow burn in the heat of a bearing. Synthetic oil is more resistant to heat, breaks down at higher temperatures.

Just a followup that over 2 weeks later, with perhaps 30 on/off cycles, the previously offending blower is still coming on perfectly each time.

With the bonus that it now blows noticeably stronger than it's twin blower on the other side of the air handler box. (they both have identical lengths of ductwork from blower to the vents btw)

I speculate that perhaps the extra 1uF of the new cap might boost the motor some, or perhaps the deterioration of the original cap inhibited voltage to the motor a bit... at least that was the explanation I got from an HVAC tech when I replaced a cap on a home condenser fan..... which went from having to be helped with a stick to get the fan moving, to (with new cap) turning instantly and with more RPM than previously*.

In that case the difference was pure cap deterioration as the replacement cap was identical uF and physical size to the original.

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*By "previously" I mean the fan RPM when the cap was weak but once started with a stick it would ramp up to full speed. Except I didn't realize at the time it wasn't really at full speed....it was still a bit weak but I didn't know it as I had noting to compare it to.

But with new cap I was amazed how much faster the cooling fan turned....(no, didn't have a tach on it, but was much louder with new cap than before due to moving more air)

2 months and 50+ on/off cycles later, blower still perfect...

To clarify... 50+ cycles beyond the original 30...