Mep 803a overload question

[dkozma]

Hi Folks,
Asking for an experienced opinion on overloading an 803a.
Unit had a Tier 2 reset in 2012
Has 634 hours on meter.
Starts, runs smooth, 240v output
Put it under load 50%, voltage rock steady, amps drop to 58.5
Put it under load at around 105% (57amps) a little smoke, some dry carbon spitting out , voltage steady,
amps drop just a skoach to say 57 and a few points, holds for about two or three minutes and cuts out
on overload.
This seem about right?
I know it's correct as far as the tables say, but should it handle more?

 

[Zed254]

You mention smoke and dry carbon spitting out at 105%: this sounds like some wet stacking. Have you run it at say.....75% for an hour or two?

Search the forum for wet stacking and you'll get details on it. However, if that machine is not new to you and you've run it at 100% before for an hour or so with no problems it won't be wet stacked.

Is the machine new to you?

Exercising switches often helps, too: https://www.steelsoldiers.com/showthread.php?147714-MEP-803a-overload-circuit

 

[jamawieb]

At 57 amps at 240v is 13,680 watts. I would say its working perfect but it could do a little better. I load test mine at 14kw for several hours before I sell them, anything over 14kw it will trip the overload.

 

[uniquify]

Hi Folks,
Asking for an experienced opinion on overloading an 803a.
Unit had a Tier 2 reset in 2012
Has 634 hours on meter.
Starts, runs smooth, 240v output
Put it under load 50%, voltage rock steady, amps drop to 58.5
Put it under load at around 105% (57amps) a little smoke, some dry carbon spitting out , voltage steady,
amps drop just a skoach to say 57 and a few points, holds for about two or three minutes and cuts out
on overload.
This seem about right?
I know it's correct as far as the tables say, but should it handle more?

Do you by chance mean the frequency (hertz) is dropping as the load (amps) increases?

It's fairly typical for the frequency to drop a little as the load increases. Many folks will set the frequency around 61 or 62 hertz (no load) so that it's closer to 60 hertz when a larger load is being supplied.

 

[Light in the Dark]

Starts, runs smooth, 240v output
Put it under load 50%, voltage rock steady, amps drop to 58.5
Put it under load at around 105% (57amps)

At 50% load, whats the real amps... dont think its 58.5?

 

[Dock Rocker]

At 50% load, whats the real amps... dont think its 58.5?

I am guessing he is talking about Hertz.


Sent from my iPhone using Tapatalk

 

[dkozma]

Dock Rocker, you are correct. I meant to say Hertz.
Jamawieb, great input. I'll adjust my load bank and run at 100% for several hours and burn out
any carbon. No noticeable went stacking evident externally. Then I'll measure it's overload cut out threshold
accurately.
Thank you guys.

 

[Bmxenbrett]

Its normal to drop some HZ after the load is applied. This is why you set the HZ after a normal load is on the set.

 

[Dewie38]

Set the load to 100% rated kW and set the freq to 60 Hz.
Remove the load and the freq should be somewhere around 61.5 to 61.8 Hz.
The sets were meant to run at 3% freq regulation, 60 Hz full load and 61.8 Hz max at no load.