C1: Voltage regulator

[Rob M.]

Hi all,

Another question: after driving a bit through the countrysite I decided to try a piece of highway since next week we have to make a longer drive and I wanted to be sure it would handle fine on the highway too.

I noticed the temperature again raised from 180 to almost 225 in a few seconds. Then I noticed the load current was 30+ A. when I was driving in the above 2500 rpm area (4th gear, no lights or radio, heater fan on high). When the rpm was lowered to 2000 (by slower driving) the loading current was back in the 15 A. area and temperature was immidiately back to a more acceptable level (180F). Since the load current depents on the output voltage of the voltage regulator and what is switched on on a particular moment I fiugured the load voltage was to high and therefor the temparature gauge was giving an incorrect reading (temp = loading voltage devided by resistance of the temperature sensor). After measuring the loading voltage at higher rpm I noticed it went up as high as 18 Volt which I gather is quite high. I would expect a maximum loading voltage of appr. 15 Volt. I tried a second voltage regulator which was configured at the same time as the currently fitted but it resulted in the same readings. Should I get both voltage regulators readjusted to get a 15 volt output at higher rpm's (3000 - 5000 area) ?

thanks for any suggestions,
Rob Musquetier
Cloacks Country (NL)




The C1 1959 Corvette Restoration Project

[Jack H.]

Re: C1: Voltage regulator

You're understanding is CRYSTAL clear, Rob. It's very unusual for a v-reg to call for that much charging voltage and with two v-regs doing the same thing, I'd start to suspect there's "something rotten in Denmark" (Shakespere, Hamlet).

Once you've overcome the recharge required from initially cranking/starting the engine, a fully charged battery should result in a steady-state voltage reading at the battery of 14-15 VDC that shouldn't change too much vs. engine RPM. If your measured battery voltage, at speed, is really climbing to 18 VDC then you need to understand what's changing and fix it.

Basically, if the v-reg is defective OR it 'thinks' it's seeing a VERY low battery in need of charging (wiring burned, contacts oxidized....). A good auto electric shop ought to be able to diagnose what's happening with your charging system on the car....

[Bob Simard]

One possibility -

If the field screw (bolt, whatever) on the generator (the one with the red lable on it) shorts to the housing, the gen will put out max voltage. Check for a short there. Smoked my generator in a couple of hours on a road trip leaving Bend Oregon.

[Rob M.]

Re: One possibility -

Bob,

This might have been the cause due to the shielding. I've removed the regulator, tested it, it looked just fine and build it back in and now it works fine. I'm still a bit puzzled why the current drain was so high...

greetings,
Rob.