337 Voltage Regulators

[ron minichello]

Needing Part # C611002-0105 28 VOLT VOLTAGE REGULATORS IN ANY CONDITION.. ( NEW USED OR REBUILDABLE CONDITION ) E-MAIL RJM8484@EARTHLINK.NET OR CALL 1-336-623-4704

[WebMaster]

the zeftronics unit will work in your skymaster, and last i checked, they were $30-$40 at aircraft spruce

[KyleTownsend]

I just bought two of the zeftronics units direct. They were around $100 per. Haven't installed them yet.

Curious to know how everyone is dealing with the famous "flickering lights" of the Skymasters.

It's been my experience that it's not much of an issue when everything is just right (voltage regulators well calibrated; switch, fuse and wire resistance OK, etc.). However, I have had a couple of rounds with it (one right now).

I am really tempted to do a STC for installing a simplified system with paralleling (3-wire) regulators (ala Tom Carr at CPA). Supposedly, this helps the flickering / nervous ammeter problem, and is much better at insuring that the alternators share the load evenly. Curious if anyone has done this and how it worked out.

kt

[Jerry De Santis]

Kyle, The Voltage Reg. are adjustable. A good mechanic should be able to do it and tune each one in.

Jerry
N34EC

[Mark Hislop]

Kyle:

Define flickering lights. If you are referring to the amber alternator lights flashing on and off as the alternators take turns picking up the load, the paralleling regulator modification will help. If you are referring to the rapid flickering of your instrument lights, the regulator mod will not help that. The flickering of instrument lights is due to rapid voltage fluctuations. This is caused by resistance in the regulator circuit. The resistance can be in dirty or corroded connections, the field circuit breakers, the alternator field switches, or the master switch. It takes a very little amount of extra resistance to make the system start to "hunt" or chase, causing the voltage to rapidly rise and fall, casuing the lights to get brighter and dimmer.

The good news is that the problem is not terribly expensive to fix. Clean all connections in the field side of the alternator and regulator wiring. Replace, if required, the alternator field switches, the master switch, and the field circuit breakers. Your lights will stop flickering, at least for a while.

Mark

[Dale Campbell]

I have spent many dollars trying to stop the blinking lights.
I had the parallel system put in. Had both coupling replace on two alternaters. Had one new alternator installed. New battery, all diodes on fire wall replaced in regulators circuit. Some wiring replaced. Some breakers replaced. Each time the A&P said it is ok.
Well each time it was for about 10 hours. Then the lights start the blinking again. It does it more when battery is up to full charge. If you turn on a lot of devices to demand more electric power they do not blink as much. But you will never get it to stop for good. I finally gave up and just live with it. Good luck!!! Dale

[linnflohr]

Originally Posted by Mark Hislop

Kyle:

Define flickering lights. If you are referring to the amber alternator lights flashing on and off as the alternators take turns picking up the load, the paralleling regulator modification will help. If you are referring to the rapid flickering of your instrument lights, the regulator mod will not help that. The flickering of instrument lights is due to rapid voltage fluctuations. This is caused by resistance in the regulator circuit. The resistance can be in dirty or corroded connections, the field circuit breakers, the alternator field switches, or the master switch. It takes a very little amount of extra resistance to make the system start to "hunt" or chase, causing the voltage to rapidly rise and fall, casuing the lights to get brighter and dimmer.

The good news is that the problem is not terribly expensive to fix. Clean all connections in the field side of the alternator and regulator wiring. Replace, if required, the alternator field switches, the master switch, and the field circuit breakers. Your lights will stop flickering, at least for a while.

Mark

Where is the data on the paralleling ? I had my field CB blow and found out we do NOT have true electric redundancy . Emergency situation if you are IMC!

[linnflohr]

Originally Posted by Mark Hislop

Kyle:

Define flickering lights. If you are referring to the amber alternator lights flashing on and off as the alternators take turns picking up the load, the paralleling regulator modification will help. If you are referring to the rapid flickering of your instrument lights, the regulator mod will not help that. The flickering of instrument lights is due to rapid voltage fluctuations. This is caused by resistance in the regulator circuit. The resistance can be in dirty or corroded connections, the field circuit breakers, the alternator field switches, or the master switch. It takes a very little amount of extra resistance to make the system start to "hunt" or chase, causing the voltage to rapidly rise and fall, casuing the lights to get brighter and dimmer.

The good news is that the problem is not terribly expensive to fix. Clean all connections in the field side of the alternator and regulator wiring. Replace, if required, the alternator field switches, the master switch, and the field circuit breakers. Your lights will stop flickering, at least for a while.

Mark

Where can I find the info on paralleling please?

[hharney]

http://www.337skymaster.com/messages...ht=Paralleling

http://www.337skymaster.com/messages...ht=Paralleling

[n86121]

You just have to realize these are flying dinosaurs. The voltage will drool up and down a bit, and so will your panel lights. If you have a digital voltage gauge somewhere you will see even cars do the same, as the battery and alternator and loads chase each other around.

Once way to fix that panel light issue is to voltage limit the supply side reference voltage of the dimmer circuit, the NPN TO3 transistor to a constant source. For example, a 20 volt zener diode to ground with a resistor to b+, then feed the totally stable 20V into the top of the reference for the dimer circuit. Now you have literally voltage regulated lighting.

Of course, I am not familiar with any FAA approval to do so.

[LostKiwi]

My airplane came with the 60 amp alternators, and the Zeftronics regulators installed. There doesn't seem to be any adjustment available, but I don't get any weird flickering lights.

I do have a volt meter and dual ammeters. She's pretty stable, has about a 10amp draw with everything turned on.

One observation I've made is that a good charge in the battery seems to make the whole thing run nicer. If the battery is low for one reason or another, the front alternator will output a much higher voltage, to the point where it can kick the rear alternator offline.

If I've been away for a period of time (I travel a lot due: work) I make a habit of pulling the battery and throwing it on charge for an hour or so. A battery minder would probably be a good investment.

Leighton.

[DrDave]

Lostkiwi:

Does the voltage on the front alternator rise or does the current from the front alternator go up?

If it is the latter, which makes more sense, the front alternator is sensing the load more than the rear alternator. This can be resistance in the field circuit, output side, or ground circuit. Please report more information.

Dave

[rrice]

I have a couple of 337 regulators from our 337c. Need to check the numbers.