C1 voltage regulator mystery

[Troy P.]

The 55 Corvette used the 1118826 voltage regulator which is the same unit that came in passenger cars with one or more of the power steering, air conditioning, and (I believe) power top options. The standard 55 voltage regulator for US cars was 1118945 and for Canadian cars was 1118825.

The 826 regulator has a greater current output (27-33 amps) than the other two (23-27 amps). This makes sense in cars with high load electrical options such as air conditioning, power windows, and power tops. But I don't see why this extra output was needed for hydraulic power steering or for the Corvette.

The other thing I don't understand is why Canadian cars would come with a different part number regulator that has the exact same specs for cut-out, current and voltage regulation as the stock regulator used in the US. I assume Canadian cars had negative ground like the US cars.

Any thoughts on this?

[John S.]

Re: C1 voltage regulator mystery

passenger cars were designed with generators that were approximately two inches shorter than the corvette generator. they could only put out 25 amps.

[Mike M.]

Re: C1 voltage regulator mystery

The 55 Corvette used the 1118826 voltage regulator which is the same unit that came in passenger cars with one or more of the power steering, air conditioning, and (I believe) power top options. The standard 55 voltage regulator for US cars was 1118945 and for Canadian cars was 1118825.

The 826 regulator has a greater current output (27-33 amps) than the other two (23-27 amps). This makes sense in cars with high load electrical options such as air conditioning, power windows, and power tops. But I don't see why this extra output was needed for hydraulic power steering or for the Corvette.

The other thing I don't understand is why Canadian cars would come with a different part number regulator that has the exact same specs for cut-out, current and voltage regulation as the stock regulator used in the US. I assume Canadian cars had negative ground like the US cars.

Any thoughts on this?

check with the team leader, dave brigham, as i believe the next judging manual will have different info for the volt. reg.mike

[John S.]

Re: C1 voltage regulator mystery

i believe the 825 and 826 have the same voltage output. the 945 regulator and it's generator are 25 amp that increase output at lower speeds. the 945 is not to be used on vehicles driven for long periods at sustained high speeds. the 825 and it's generator are 30 amp and have a medium cut-in at highway speeds. the 825 has a supplement wire from the generator to battery through the regulator to carry additional output.

[Dan D.]

Re: C1 voltage regulator mystery

Thank you very much guys! My 57 came equipped with a Delco rebuilt generator (but appears to be an 043) and a 945 regulator. Never knew what the 945 regulator was off of; it has top screws. I was going to post here on the forum, but now I don't have to. I don't like the answer too much, but at least I know. -Dan-

[Troy P.]

Re: C1 voltage regulator mystery

Cars with power steering used the same generator as the Corvette as well as the same regulator. So perhaps there is a generator/voltage regulator combination issue that explains some of it.

Still it would be interesting to know why the lower amp Canadian and US regulators differ and why cars with hydraulic power steering and Corvettes were demmed to need a greater current output when they have no obvious greater need than the typical car.

[Dan D.]

Re: C1 voltage regulator mystery

The Corvette needed the 043 generator for the tach drive. That would explain why pass power steering and Corvette are the same. So the question is why the pass power steering needed higher current.

AC was available in 56 pass, (I saw one way back), so perhaps they just made it standard. AC and power steering were both high end options back then, perhaps most people getting AC also wanted power steering. Just a thought. -Dan-

[John S.]

Re: C1 voltage regulator mystery

Cars with power steering used the same generator as the Corvette as well as the same regulator. So perhaps there is a generator/voltage regulator combination issue that explains some of it.

Still it would be interesting to know why the lower amp Canadian and US regulators differ and why cars with hydraulic power steering and Corvettes were demmed to need a greater current output when they have no obvious greater need than the typical car.

the only lower voltage regulator for a 55 listed in part books is the 945. the 53-55 corvette parts guides and all chevy parts guides list the 825 as the higher voltage regulator used on corvettes. the question to me is why do all part books list the 825 and not the 826 as the regulator for a corvette. as for the higher current output it is used for extended high speed use, which corvettes with their solid lifters and hotter ignitions (.3 ballast resistor on corvette versus 1.8 passenger car) were being designed for racing.

[Troy P.]

Re: C1 voltage regulator mystery

I believe the parts book is wrong on this one. (I've noticed a few other errors over the years too but can't recall them right now.) The correct 55 Corvette regulator is the 826 - according to research reported on original cars. This is definitely the regulator used on 55 cars with power steering too.

They did have an air conditioning option in 55 also. You can see how AC and power top would add to the electrical load. But power steering? I guess it may all have to do with what generator was available with an output shaft to run the power steering pump and tach drive.

[Chris H.]

Re: C1 voltage regulator mystery

If there is any interest I have these drawings:

1119001 regulator outline 1119000 regulator outline 1119002 regulator outline 1118826 regulator outline 1119234 regulator outline 1119261 regulator outline 1119305 regulator outline 1119515 regulator outline

[Jack H.]

Re: C1 voltage regulator mystery

There are other characteristics of the electrical system that you're missing by simply concentrating on output current specs. How about the electrical system's cut-through profile?

Then, there's the aspect of engine electrical consumption. Back in the early to mid 50's, the lion's share of passenger cars went out the door with low rev, 6-cylinder, engines. From '55 forward, Corvette was rather unique in having V-8 power and being aimed at high RPM operation. That impacts electrical consumption.

So, there are a number of considerations when it comes to sizing and selecting the voltage regulator and companion generator. Some may be inobvious...