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Niagara Air Parts Alternator and O/V Protection

Finley Atherton

Well Known Member
I see that Niagara Air Parts that supplies the ND internally regulated alternators for Canadian Aero Manufacturing (CAM) that Aero Sport Power uses on their engines, sells an over voltage protection unit for their 40 amp alternator. www.niagaraairparts.com My understanding is that this alternator is a well built, reliable unit with existing built-in protection including O/V protection. The pdf on the Niagara Air Parts site details two possible failure modes for the alternator that could cause O/V. My questions. Is it really necessary to add this extra O/V protection? Are there any confirmed cases of O/V in the Niagara Airparts Alternator ? I have the warning light and the engine monitor O/V alarm and I would pull the 40 amp breaker on the "B" lead if I ever saw an over voltage.

Fin 9A
Australia :confused:
 
No O/V protection

Finley Atherton said:
I see that Niagara Air Parts that supplies the ND internally regulated alternators for Canadian Aero Manufacturing (CAM) that Aero Sport Power uses on their engines, sells an over voltage protection unit for their 40 amp alternator. www.niagaraairparts.com My understanding is that this alternator is a well built, reliable unit with existing built-in protection including O/V protection. The pdf on the Niagara Air Parts site details two possible failure modes for the alternator that could cause O/V. My questions. Is it really necessary to add this extra O/V protection? Are there any confirmed cases of O/V in the Niagara Airparts Alternator ? I have the warning light and the engine monitor O/V alarm and I would pull the 40 amp breaker on the "B" lead if I ever saw an over voltage. Fin 9A
Australia :confused:
I understand your :confused: emoticon. I know how you feel and have this alternator. Good news is I researched this and can share some insight. I did not see where Niagara gives two O/V scenarios.

The O/V module they sell is from Ziftronics. They make FAA approved electrical stuff for old factory birds. This O/V product is an add on for OLD airplanes with OLD voltage regulators, which ARE subject to O/V. The modern ND alternator that Niagara sells, internal regulated, is not like old alternators with external regulators. The old systems on many factory planes is based on 40 year old technology, about as sophisticated as a 1960's Chevy or Ford, so they need an O/V module. Niagara did not offer the O/V modules until the last few years when Bob N. of Aeroelectrics started scaring people with stories of gloom and doom. When asked Bob really had no facts. Most of the O/V conditions are old stories of old alternators with old mechanical external regulators. The stories where shrouded urban legend and exaggeration.

If for some reason you must have a O/V module I have something better and cheaper than the Ziftronics unit, but I DON'T recommend adding on ANY O/V module.

The likely hood you will have an over voltage is slim to nil. There is no guarantees in life, but NO O/V conditons have ever occurred with this alternator in the 10 years they have sold it. One unit is well over 10 years and +1000 hours in flight time. Different but similar Nippondenso (ND) alternators have a very good reliability record. There have been some anomalies with OTHER ND models like the Niagara unit, but I can track down the two main causes in all cases but one. One, the pilots turned the alternator on and off under load in flight. Don't do that. Two, many problems occure with rebuilt alternators or with aftermarket Chinese clone units, not new original manufactured ND units.

The Niagara unit is a new ND unit last I heard. I don't trust the rebuilds. A new original ND unit is best in my opinon, quality wise. The good news most O/V conditions regardless of cause was mild, like 16 volts or 17 volts. So even if you got some kind of voltage instability or high voltage it's not going to be the run-a-way, makes the battery explode event.

There was a one case where a ND alternator (NOT a new Niagara unit) made the battery "Get Fat" and damaged it. The Gent was flying around may be for 30 to 60 minutes with an O/V conditon? He did not know how long or how high the voltage got. He smelled something burning, his battery, and turned the alternator off with the IGN/ALT switch successfully. Clearly an OV condition occurred. Also this shows an O/V indicator is a good idea. By all means connect the warning light on the alternator. If he would have noticed sooner and turned the alternator off, he likely would not have had battery damage. Again this was an aftermarket clone or rebuilt alternator he just put on. This is the worst thing I ever have heard of that I can verify, and I think this was pilot error.

Look all alternators fail at some time. Even the BIG buck B&C units have bad days.

With the Niagara unit, you may want to start inspecting the brushes about 400-500 hours and evey 100 hours thereafter; think about brush replacement in 500-1000 hours. There was one case of brushes failing at 800 hours. They may go a lot longer, 2000 hours, depending on how high you fly and in what conditions. Low humidity at altitude is hard on the brushes.


The caveat to the Niagara is wire it and operate it as Niagara suggest. They suggest a single master/alt switch (DPST - Double Poll/Single Throw). The IGN wire gets a CB. If you use a single switch, I suggest you consider a pull-able CB. The single switch keeps you from making a mistake and turning the alternator off or back on while running. For some reason pilots feel the need to play with switches needlessly.

Please don't cycle the alternator switch or CB on/off anytime the engine is running. The ALT or IGN wire pwr is not designed to turn the alternator on and off while under road (being turned by the engine). This is how it works in a car and therefore you should follow that application. Do you have an alternator switch in a car?

If the alternator dies in flight than by all means pull the IGN wire power by pulling the 5 amp CB as Niagara shows. Actually a 1 or 2 amp CB will work. The IGN wire current draw is mili-amps. Unlike a "field wire" the IGN wire is just a signal to "wake" the alternator up, get ready to go to work or to go back to sleep. A field wire actually controls the output of an alternator by varying the "Field" voltage. This is typical of external voltage regulators. That is not the function of the IGN wire with an internally regulated alternator like this ND unit.

To assure complete isolation of the alternator I recommend you use a pull-able CB on the B-lead, where the Niagara diagram shows a 40 amp CB. A 40 to 50 amp pull-able CB is fine. In case the alternator failed in flight you could disconnect the B-lead from the plane. (you mentioned this)

It's popular to use a fuse on the B-lead of the alternator so you can wire direct to the battery. Bob N. of aeroelectrics recommends this. It does simplify the wiring because you can make the b-lead shorter and wire it directly to the battery (with an in-line fuse). The myth is the b-lead is noisy, so not running the b-lead to the instrument panel makes less noise. Well this is not true with a modern solid state alternators like the ND unit Niagara sells. It just does not matter, they are quite regardless.

Run the b-lead wire to the panel mounted CB, than to the main bus, which is the way every certified general aviation airplane is typically wired. This is what Niagara shows.

The noise issue is a throw back to old generators and old mechanical voltage regulators. Other wise just follow Niagara's wire diagram. The b-lead coming of the Niagara unit is quite no matter how you wire it.


Plane-Power

I mention aftermarket ND alternators are not as good as original ND parts. Well an exception is Plane Power's units. They use better aftermarket parts and do custom stuff. Plane-Power units are sold by Van. They are a little more $$ but you get more Amps, aluminum pulley, counter clockwise fan rotation, high altitude brushes and the extra O/V module. The O/V module bolts right onto the alternator unit.

Both Plane-Power and Niagara have a nice units. If I had a highly electrically dependant airplane, planning IFR operations, I'd consider the Plane-Power unit.

For most RV'ers the Niagara unit fine. If you want EXTRA O/V protection or think you want it, I would buy the Plane Power unit first. Trying to add O/V protection to an internal voltage regulated alternator is a mess. Plane power did it right. The O/V relay method on the b-lead makes more problems than solves. It adds lots of weight and cost, about $100. By the time you buy the add-on O/V to the Niagara unit, you could buy the PP unit.
 
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