Interesting voltage drop

   / Interesting voltage drop #1  

woodlandfarms

Super Member
Joined
Jul 31, 2006
Messages
6,117
Location
Los Angeles / SW Washington
Tractor
PowerTrac 1850, Kubota RTV x900
So today, mowing, I noticed my volt meter reading a low 12.5... Generally I am mid 13's... Well, tinkered around and found that my PTO and my draft control are the culprits...

Just wondering if this is normal. I know I am drawing amps with these devices, I just didn't expect to see the voltage drop (I get it when I am running my lights wich are 220 watts total...
 
   / Interesting voltage drop #2  
The PTO and draft control are probably solenoids of some sort. So if you shut the lights off, with PTO and draft control on, does the voltage come back up?

What's the alternator capable of? I'd think one could expect some voltage drop. As the load on that type of generation systems increases, the voltage will decrease eventually to the point where it won't do some of the things you want it to do, like say charge your battery. I donno though if your seeing abnormal operation.
 
   / Interesting voltage drop
  • Thread Starter
#3  
I don't know if this is abnormal or not. I think it is not but the other day my breaker blew twice for no preceptable reason. It has not popped since. Yes voltage returns to normal so alt appears to be good.

I have 65 amps on the alt, so lots of room unless these big magnets pull lots of juice.
 
   / Interesting voltage drop #4  
I don't think the two solenoids would cause a voltage drop normally so I would look for bad connections as the cause of the voltage drop or an short. Both get power through the ingnition switch via the accessory circuit which also supplies the hydraulic cooler fan. Given the breaker issue you experienced I suspect you have a short in one of the components--perhaps only a minor leakage when you see the 12.5 volts and a bigger leakage when the breaker trips.
 
   / Interesting voltage drop #5  
might be inadequate wireing, grounds or charge capability vs load.

what ar ethe particulars?

load?

charge amps?

wire sizes / runs? terminal end types?
 
   / Interesting voltage drop #6  
Im thinking with the breaker problem, that i'd check for abraded insulation. Seems like that system would be designed to function without blowing breakers.
 
   / Interesting voltage drop
  • Thread Starter
#7  
It hasn't done it since and I have about 12 hous of mowing in.... Going to waiypt this out...
 
   / Interesting voltage drop #8  
What was the engine revs? An alternator does not put out as much current at idle. If you rev it up and the voltage goes up, then the alternator is ok. It make take a few minutes of higher revs to bring the voltage up.
 
 
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