Replacing ES52 on 1997 PowerTech 8KW generator
I've been battling a generator overspeed error that generally happens 20 to 45 minutes after starting the generator for a couple years. Generator runs fine and then the ES52 abruptly shuts down the generator without any change in voltage or "sound" of the generator. It seemed to happen more quickly in the summertime when running down the road. Once shut down on the road, it might restart and then immediately shut down again from an "overspeed" error. All other systems appeared fine. I checked the transformer that sends a speed signal to generator, solid 60HZ and no apparent overheating problems. Replaced the fuel shut off solenoid. No change. Operated with the cover off the generator control box and door open. Ran for over an hour until I shut it down. The speed sensor wire had been crimped at one time and I cut the end off and attached a new ring terminal. I replaced the speed sensing wires and put a twist in them as recommended in the ES52 manual. No change.
Jeff at PowerTech suggested it might be a bad ES52. I surmise it was suffering from heat fatigue. It worked perfectly when the environment around it was cool, but as the control box got heat soaked from a running generator the ES52 would "break down" with an overspeed error. This summer I ordered a new one from a generator supply house and discovered that from 1997 to 2024 there had been quite a few changes in the connections on the ES52. It was like a database conversion, I had to remap all the connections based on a careful study of the original PowerTech wiring diagram and the wiring diagram provided with the new ES52. It was necessary to go from ring terminals to clamp connections. The 12volt red power wires and ground wires were doubled up on the original ES52, but they did not both fit in the new ES52 terminal block. The description of the connections on the new ES52 and the old were different and in a different order. After studying the manuals and wiring diagrams for way too long, I created a test bridge with a twelve terminal wiring block. This way I could easily re-install the old ES52 if I couldn't make the new one work. Miraculously it worked and I've now hard wired the new ES52 into the control box. Here is my conversion table:
Topic: Replacing ES52 on 1997 PowerTech 8KW generator