Voltage Regulator

How to keep the Cessna 170 flying and airworthy.

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Voltage Regulator

Postby azmuth1 » Thu Oct 21, 2010 3:11 pm

I am getting variable charging from my voltage regulator, from 0 at flight RPM to 4 amps at taxi RPM, so I am going to replace it. I am looking for references to finding to correct replacement. (1949 170A, 145-2, original style generator). One guy wants to install a Delco from the auto store, saying it is the same thing without the FAA sticker. I want to install the correct one.

Thanks,
John
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Re: Voltage Regulator

Postby canav8 » Thu Oct 21, 2010 4:19 pm

John be careful it depends on which generator you have. 20 amp? 35amp? yes the actual regulator was commonly found in automobiles but there is a company in Kentucky I believe that rebuilds the generators and sells new regulators. I gotta go to the hangar to get the name. Or you can do a search on this forum board. This has been covered in the past.
viewtopic.php?f=2&t=7787&hilit=regulator
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Re: Voltage Regulator

Postby Bruce Fenstermacher » Thu Oct 21, 2010 4:43 pm

John, here is a thread I started for just this purpose. viewtopic.php?f=2&t=7787&start=0&hilit=voltage+regulator

About the third post down is a table of part numbers I compiled.

Most of the rest of the thread has info how to determine what you have already which may or may not be an aircraft part.

Doug is correct. You must get a regulator to match your generator.

My advice if I was to replace a voltage regulator is to buy the electronic model available from Zeftronics. I've never heard of someone not happy with theirs. http://www.aircraftspruce.com/catalog/e ... icsreg.php
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Re: Voltage Regulator

Postby 15A » Fri Oct 22, 2010 2:22 am

My advice if I was to replace a voltage regulator is to buy the electronic model available from Zeftronics. I've never heard of someone not happy with theirs. http://www.aircraftspruce.com/catalog/e ... icsreg.php


Bruce, You're going to hear it now!
My Zeftronic VR would shut-off after a couple hours flying time. Sent it back and they found nothing wrong. The problem persist.
The final determination we came up with was that there had to be a bad ground somewhere. I was told the slightest 'spike' would trip that VR and shut it off.
Each time it went down, I'd cycle my master switch, and it would come right back. I eventually bought another off ebay 8O and switched it out. It's been fine since!!! Knock on wood! Hind sight tells me I should have stayed with the old points VR!
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Re: Voltage Regulator

Postby N2255D » Fri Oct 22, 2010 1:52 pm

Noting is perfect but I've had a Zeftronics VR installed for 12 years with no problems.
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Re: Voltage Regulator

Postby gahorn » Fri Oct 22, 2010 2:13 pm

azmuth1 wrote:I am getting variable charging from my voltage regulator, from 0 at flight RPM to 4 amps at taxi RPM, so I am going to replace it. I am looking for references to finding to correct replacement. (1949 170A, 145-2, original style generator). One guy wants to install a Delco from the auto store, saying it is the same thing without the FAA sticker. I want to install the correct one.

Thanks,
John


Joe, if you truly have your "original" regulator, the PN is 0413205, which is a 20 amp VR. The Delco-Remy PN is 1118736, and the ElectroDelta PN is 1118904. The "correct", genuine aviation FAA-PMA part can be obtained from Aircraft Spruce, (877-477-7823) THEIR PN 07-00899 for about $160.

The Zeftronics unit is also available, and is a good product, but Spruce does not list the 20 amp unit. You need the Zeftronics G1200N for a 20 Amp generator. NEVER install a higher capacity regulator than the generator output. It's important to match regulators to generators with regard to amperage, if you wish to have maximum output without burning up the generator. (A lower amperage regulator is OK and will not cause damage, but will limit the higher-amperage capacity generator to the maximum value of the regulator. A higher amp reg. will burn up a lower-amp generator.)

http://www.zeftronics.com

Zeftronics.pdf
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Re: Voltage Regulator

Postby lowNslow » Fri Oct 22, 2010 2:19 pm

gahorn wrote:The Zeftronics unit is also available, and is a good product, but Spruce does not list the 20 amp unit. You need the Zeftronics G1200N for a 20 Amp generator. [/attachment]

If you go to toward the bottom of the Spruce page linked above they do have the Zeftronics G1200N (p/n07-00617) listed for $140.
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Re: Voltage Regulator

Postby gahorn » Fri Oct 22, 2010 2:27 pm

lowNslow wrote:
gahorn wrote:The Zeftronics unit is also available, and is a good product, but Spruce does not list the 20 amp unit. You need the Zeftronics G1200N for a 20 Amp generator. [/attachment]

If you go to toward the bottom of the Spruce page linked above they do have the Zeftronics G1200N (p/n07-00617) listed for $140.


How strange. When I accessed Spruce's "voltage regulator" page it displays one without the G1200.
http://www.aircraftspruce.com/catalog/e ... volreg.php

You're right...the Spruce "Zeftronics" page does show it. :roll:
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Re: Voltage Regulator

Postby 15A » Fri Oct 22, 2010 3:06 pm

I do like the Zeftronic VR. Unfortunately I had some minor issues, but they were cleared up. Tech support was excellent.
But, just for a 'heads-up', grounding seems to be the root of most electrical problems. Our planes are 50+ years old. It's not a bad idea to spend a little time cleaning the grounding contact areas.
Just my experience! :wink:
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Re: Voltage Regulator

Postby jrenwick » Sat Oct 23, 2010 3:41 am

15A wrote:I do like the Zeftronic VR. Unfortunately I had some minor issues, but they were cleared up. Tech support was excellent.
But, just for a 'heads-up', grounding seems to be the root of most electrical problems. Our planes are 50+ years old. It's not a bad idea to spend a little time cleaning the grounding contact areas.
Just my experience! :wink:

Joe,

I've had the same experience with the Zeftronic regulator. I even replaced it with a new one, and it still was cutting out after about an hour of flight. The Zeftronic tech support guy suggested I make sure all the contacts to it were tight and clean, to prevent a voltage spike on the overvoltage sensing circuit. I did that to the best of my ability, to no avail. A friend suggested looking at the ground path. That rang very true to my experience, so I looked it over.

The factory-installed ground has a lot of links to it: from battery through a braid to the firewall, then an aluminum strap across the shock mount to the engine mount, then jumping over another mount to the engine. There are a lot of opportunities there for connections to deteriorate, and while this setup might have been just fine for a new 170 as equipped from the factory, it might not be good enough any more in a 55 year old airplane with advanced electronics.

I added a second cable from the battery terminal to one of the starter mounting studs, and that seems to have solved the problem. This only addresses the ground path from the battery to the engine, so I think it really only helps the starter, generator, and voltage regulator. If the avionics are spazzing out, the problem has got to be somewhere else.

I really like the Zeftronic units, and their documentation and tech support are excellent. The later units have LEDs on them that help you diagnose problems. I installed a new one in my Swift this year after an overcharging episode with a relay-based regulator, and feel much better about the whole system.

Best Regards,

John
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Re: Voltage Regulator

Postby gahorn » Mon Oct 25, 2010 3:00 pm

jrenwick.... wrote: A friend suggested looking at the ground path. ...



From "Troubleshooting the Generator/Regulator System", page 7 of The Cessna 170 Service Manual, Electrical System:
"Confirm that the voltage regulator base is grounded to the firewall and that the rubber shock mounts do not insulate it from achieving such a ground (ground strap is secure.)"

And from page10: "REMEMBER: The single most overlooked solution to generator/regulator problems is lack of proper polarization, followed by improper grounds."
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Re: Voltage Regulator

Postby jrenwick » Mon Oct 25, 2010 9:22 pm

Thanks, George. There's no such thing as too many reminders!

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Re: Voltage Regulator

Postby gahorn » Tue Oct 26, 2010 1:48 pm

jrenwick wrote:Thanks, George. There's no such thing as too many reminders!

John


And also Remember, the author of that manual is an idiot. "The single most overlooked solution to generator/regulator problems is lack of proper polarization, followed by improper grounds." ... is not a single issue, but TWO issues. :oops:
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Re: Voltage Regulator

Postby N2255D » Tue Oct 26, 2010 2:24 pm

gahorn wrote:
jrenwick wrote:Thanks, George. There's no such thing as too many reminders!

John


And also Remember, the author of that manual is an idiot. "The single most overlooked solution to generator/regulator problems is lack of proper polarization, followed by improper grounds." ... is not a single issue, but TWO issues. :oops:

I read the sentence as The single most overlooked solution to generator/regulator problems is lack of proper polarization and the next most common is improper grounds. Guess the meaning is in the eye of the reader.
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Re: Voltage Regulator

Postby azmuth1 » Fri Nov 05, 2010 2:50 am

FYI...here is what was found to be the cause.

I guess a gremlin was the cause. The gen was pulled because the VR didn't solve the problem. The Gen Shop said it was charging as a new one. Re-installed. Used an alligator clip to the post to test amps and all ok. Installed the wires on the gen post and tightened the nut...the gremlin was laughing again! :lol: Yes..removed the gen again after suspecting a loose post mount; found the gen post was not making constant contact due to the pull of the nut on the post. The post problem was not found at the shop the 1st time because they also used a clip when testing. Repaired and all is well for now.

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