Crown RC3000:
high speed cut out

looking for advice. we have a rc 3000 both forward and reverse work until the 1a contactor pulls in. 1a pulls in and cuts out with in seconds and i loose forward or reverse. once control hand is back in neutral and moved to forward or reverse it works again until high speed
  • Posted 19 Dec 2018 03:07
  • Discussion started by luke123
  • Saskatchewan, Canada
Showing items 1 - 8 of 8 results.
thanks for the input, it was a loose connection on the card
  • Posted 10 Jan 2019 07:10
  • Reply by luke123
  • Saskatchewan, Canada
Possibly something wrong with the 1A contactor like the contact tips not making a good connection???
  • Posted 2 Jan 2019 22:22
  • Reply by mrfixit
  • New York, United States
of course, and knowing the crown design and GE EV100 design i agree, it probably isn't the 1Rec causing the 1A contactor to drop out. (i was just stating my view on what you had said earlier).

As you say it may be the pot just not getting to the range the logic is looking for to allow the card to reach the 80% or above pulse rate it wants to see before telling the 1A to pull in. It could also be some internal setting in the logic card itself causing a PMT or 1A timing issue or some 1A thermal problem causing it to drop in and out as he described.
Replacing the pot would be easy enough for starters providing it checks out to be faulty.
The fact that it only cuts out after 1A pulls in and returns back to normal SCR operation (without cycling the key) leads me to believe it may be something else but checking the pot would probably be one of the first things i would do before going on to other possible causes.
If he were to check it and find a glitch then yes a pot doesn't cost much and as i said is easy enough to replace and setup.
Things he should probably check for:
-If the pot shaft has slipped and gotten out of adjustment
-when testing doesn't read the expected 4300 to 4600 ohms and 5000 ohms when within 2deg of neutral position, and 0 to 200 ohms when in full fwd/rev or shows erratic changes during the sweep of it's internal wiper.
-And yes, there are those peksy switches to rule out too ;o)

Now being this unit probably has an LX logic in it there are no 1A switches on the control handle controlling the 1A circuit so we can rule out that possibility. Verifying the readings on the pot sweep will tell the tale.
  • Posted 2 Jan 2019 06:51
  • Reply by swoop223
  • North Carolina, United States
You've been swooped!
The reason I ruled out the rectifier, there are no codes...and he doesn't have to re-key the truck. That points me to the traction pot. With a fleet of 30 RC3000's , with most over 20,000 hrs, I've only replaced (1) 1rec.....countless 4 recs, and about 15 pots with this same condition. Of course, assuming all the switches test good.
  • Posted 1 Jan 2019 18:33
  • Reply by Ifixit
  • Pennsylvania, United States
actually i've seen many #1 Rec's and 2 and 5's as well test good with a meter, or even a handyman tester in normal mode and still be faulty. Truck would run but still fault out intermittently because of an internal fault inside the Rec. The handyman tester has a 'leak test' mode where you can check for bleed back through the rec and this usually tells the tale. When you run the test if it turns on the leak light of course replace the rec, even if just blips for a second thats an indication the rec has issues. So the notion that it either works or not 'on or off' is a misnomer (misconception). Just a couple milivolts of feedback can cause one to fault and may not show up under normal testing.
In a perfect world or from a trainer's view though you are correct, most of the time it's either on or off, working or broken ;o).
  • Posted 31 Dec 2018 11:10
  • Modified 31 Dec 2018 11:11 by poster
  • Reply by swoop223
  • North Carolina, United States
You've been swooped!
The 1 rec either works, or it doesn't. Same with the 2 and 5 rec turning it on and off.
  • Posted 31 Dec 2018 04:56
  • Reply by Ifixit
  • Pennsylvania, United States
Even though the traction pot shows good resistance down to zero(full speed input), the pot is actually bad. The traction card will still see milli-ohms out of that pot.
  • Posted 31 Dec 2018 04:51
  • Reply by Ifixit
  • Pennsylvania, United States
Since you do not have to rekey to travel again the GE EV-100 card is not faulting out so the problem must be what the card is not seeing causing the truck to cut out. Check your inputs to the card at the 6 screw terminals to see what you are loosing at half throttle compared to full throttle. If none of them fail then check the two bolt terminals at the 1 Rec to see if they fail.
  • Posted 24 Dec 2018 23:53
  • Reply by popeye
  • Ohio, United States

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