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MEP 003A Blew its Ammeter Circuit

reybo

Registered
... Moving Iron meters will respond to DC as well as AC so it is easy to check the movement with a D cell and a swamp resistor.
Mike
Mike,
Swamp resistor? New term to me. All the google search tells me about swamp resistors involves transistors. What don't I know?
 

Power

Registered
I think you are in the wrong place. You should go to https://www.steelsoldiers.com. There is an entire section on MEP units. Some participants are experts. For a start, visit Thread: MEP-003A problems. Post and members will tell you what happened,and where to get replacement part.
 

reybo

Registered
I think you are in the wrong place. You should go to https://www.steelsoldiers.com. There is an entire section on MEP units. Some participants are experts. For a start, visit Thread: MEP-003A problems. Post and members will tell you what happened,and where to get replacement part.
I went to steel soldiers before I came here, and found myself trapped in the Vehicle forum and could not escape. I'll have another try.
 

dependable

Registered
Are they equally suspect in causing this? The circumstance -- turning on the AC kicked the overload switch --certainly suggests a part got overloaded, not some other demon like mouse-gnawed wiring.
I was thinking arc of an overload could break a loose connection, and I've found loose connections on the units I own.

On Steelsoldiers forum, go to Auxillary equipment section, as noted above, there is a lot of info, free TMs, and helpful people who work on these all the time.
 

reybo

Registered
I was thinking arc of an overload could break a loose connection, and I've found loose connections on the units I own.

On Steelsoldiers forum, go to Auxillary equipment section, as noted above, there is a lot of info, free TMs, and helpful people who work on these all the time.
Good points. Found my way around at steel soldiers this morning and carried this thread there. 4 and 5 years ago they helped me choose an 003 and set it up.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
When you get to the root of the problem, don't forget to report back here so we aren't left hanging! :wave:
 

Radiomike

Registered
Have you managed to measure the resistance (continuity) of the meter and CT. The meter should be a very low resistance, only a few ohms, as will be the CT. If the CT or meter is open circuit then be very cautious about running the generator again.

If the ammeter is 1A full scale deflection and is a moving iron type then a 1.5V DC battery with a 1ohm series resistor (swamp) should give you some deflection on the meter. The resistor will limit the current to avoid damaging the meter. If you have another meter that reads to 1A then you can compare the calibrations.

Depending on the construction of the CT, bar or wound primary, these can be simply qualitatively tested with an AC source.

Mike
 

reybo

Registered
....
Depending on the construction of the CT, bar or wound primary, these can be simply qualitatively tested with an AC source. Mike
In the last decade, I sold every piece of test equipment I own on ebay, except a large Variac.
 

ronciecka

Registered
There are 3 CT transformers in this generator. Only one is used for single phase, the other two are for three phase. Check the resistance of all three and if one is different swap it with one of the others. If all CT transformers read the same then your ammeter is bad.
 

reybo

Registered
There are 3 CT transformers in this generator. Only one is used for single phase, the other two are for three phase. Check the resistance of all three and if one is different swap it with one of the others. If all CT transformers read the same then your ammeter is bad.
That will probably be the best guide to this.

Ran the gen during a half-hour daytime black out this week and the ammeter raised from zero to about 2%, so the meter isn't dead. I was too distracted to turn on the oven and take another reading.
 
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