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Setting limits on V3

PostPosted: Mon Sep 05, 2016 5:56 am
by Lever
The manual doesn't say much about the actual setting of the limits.

Are there any general starting points go by? It would be interesting to know about where in the pot's travel the 50% and 75% of alternator output would be. Where are they usually set from the factory?

Re: Setting limits on V3

PostPosted: Tue Sep 06, 2016 5:04 pm
by Coulomb
The pots are not set at the factory. Turn them all the way CCW for the minimum setting and then turn CW to achieve the desired value.

Re: Setting limits on V3

PostPosted: Wed Sep 07, 2016 7:26 am
by Lever
Is half way through the travel of the pot about 1/2 of the rated output of the alternator?

Re: Setting limits on V3

PostPosted: Wed Sep 07, 2016 12:05 pm
by Coulomb
Alternators are non-linear so there is no way of knowing other than adjusting with an ammeter.

Re: Setting limits on V3

PostPosted: Thu Nov 03, 2016 2:04 pm
by Lever
System is up an running with two alternators in parallel totaling 530 amps. Van is still on stands so only idle tests so far, but all looks good so far.

Question is on the limits and how they work in practice

Are the limits basically hard stops on total output based on amps or do they reduce the output a % over the entire output range? If they reduce a percent over the range, then we would see a reduction at idle compared to having the limit off, I assume, and set the limit at a speed that gives maximum output.

I currently am wired to use both limits, on for long slower charge and one for a fast 20 minute recovery, but I don't have a no limit position on the switch so it can't be run full output, which would overload the wiring.

thanks

Re: Setting limits on V3

PostPosted: Thu Nov 03, 2016 8:03 pm
by Coulomb
The limits are "duty cycle" limits that control the on/off time of field drive. As such the output current will proportional to alternator RPM. YOuy need to set the limits are the maximum RPM you expect.

Re: Setting limits on V3

PostPosted: Sat Nov 05, 2016 4:09 am
by Lever
Thanks for the information. I have set the preliminary limits and seen the progression with speed as expected. Idle amps stayed surprisingly good.

Since temperature and conditions will affect the output and alternator temps, I expect to make some minor adjustments as we use the system. For repeatability, I would like to be able to set the limits based on fully loaded field voltage, as it is easy to read while adjusting, right at the regulator.

Will a Fluke DVM be adequate and repeatable for the pulsed output of the regulator, or do I need to use a true RMS meter?

If a plain DVM is adequate, what would the maximum voltage be? I am seeing 8.7v at about 55% rated output amps for the alternators which I set for the higher of the two limits.

Re: Setting limits on V3

PostPosted: Sat Nov 05, 2016 11:52 am
by Coulomb
A normal DVM will work OK. The pots adjust the percentage of on-time so at 100% you will see about battery voltage.

Since the alternators are not linear, output versus input, exact correlation can't be made between field voltage and output current.

Re: Setting limits on V3

PostPosted: Sat Nov 05, 2016 2:01 pm
by Lever
Thanks again. I am fine with the non linearity, but do want to be able to easily get back to previous setpoints, so that should work well. I am sure it will take a few back and forth to zero in on the final settings.