MEP-018A Won't Shut Off

[Guyfang]

We're good Tom. How are things in your neck of the woods? I picked it up from a guy I did some work for. Actually bought a gin pole truck off of him and he said "I think I've got something else you may be interested in."

Now for my next question: Is the S2 toggle switch a "divided" switch? That is, is the right side of the switch not connected to the left side. I thought I had a bad switch and replaced it with an off the shelf on-off-on toggle switch and now it won't start. I have checked resistance between the negative battery cable and the contacts of switch S1. Less than an ohm of resistance between battery cable and common of S1. Meter shows open between battery cable and start terminal of S1 when in start position. Meter also shows less than an ohm of resistance between common and start terminal of S1 when in start position.

Just what switch are you talking about? S2 is the ammeter phase selector. That should have nothing to do with the start function.

 

[rebel_raider]

S2 is labeled as the Emergency Stop, Emergency Run and Normal switch in the manual(TM 5-6115-275-14 page 4-79).

 

[Guyfang]

OK, I was looking in the MEP-017A book, because the MEP-018A schematics are so rotten. I thought they would be the same. They are not.

I do remember that the S2 is a DP, double pull switch. And no, I do not remember it as being divided. Did you write up how it was hooked up originally? The wire diagrams suck. They are almost 50 years old. I am going to see if I have an older TM someplace. The old TM's had more info in them.

 

[Guyfang]

[h=2]Part number MS35059-21

SPECIFICATIONS[/h]

REACH Compliant	Yes
Status	Active
Switch Type	TOGGLE SWITCH
Actuator Type	LEVER
Body Breadth	19.05 mm
Body Height	26.92 mm
Body Length or Diameter	33.27 mm
Contact AC Max Rating R Load	20A@115VAC
Contact Current(AC)-Max	20.0 A
Contact Current(DC)-Max	20.0 A
Contact DC Max Rating R Load	20A@28VDC
Contact Voltage(AC)-Max	115.0 V
Contact Voltage(DC)-Max	28.0 V
JESD-609 Code	e3
Manufacturer Series	MS35059
Mounting Feature	PANEL MOUNT-THREADED
Operating Temperature-Min	-18.0 Cel
Operating Temperature-Max	66.0 Cel
Switch Action	LATCHED
Switch Function	DPDT
Terminal Finish	TIN
Termination Type	SCREW

It is an ON, OFF ON type, made by EATON. Write them a mail, and ask for a schematic of the switch.

 

[rebel_raider]

That's what I found too. That it was just a regular ON-OFF-ON toggle switch. I found no mention of the contacts being divided. The reason I replaced it was one of the common contacts would not contact no matter what position the switch was in. So like I said in my earlier post I replaced that switch and the set wouldn't start. I put the old switch back in just to be sure and nothing worked with the old switch, not even the panel lights. I finally tracked it down to not having a path to ground from the G terminal of the round plug from the engine. I tracked that down to the shielding on the magneto wire was not connected to the engine to provide that ground. I connected that shielding to the screw on the magneto case and now it starts AND stops with the switch. Thanks for all your help.

 

[Guyfang]

Good to go! You do good work partner.

 

[rebel_raider]

Thank you for the kind words. I hope this thread will help someone else in the future.

 

[Guyfang]

I thought about this all day. As the wire diagrams are crap for the 018A, if you ever have to do a little more work on the gen set, take the time to draw simple diagrams of the switches and what nots, and in what direction they are mounted. Add the terminal numbers, and wire numbers if you can read them. Might save you trouble one day, if you unhook something and forget how to rewire it. That's what I am doing with the MEP-802A and 803A. Don't have to do it all at once, just when ever you have a few seconds, or have to work on it. Just a thought.