3 phase 208 help

[Kemp3]

I apologize I have searched and found nothing on this subject. I have a 15 KW heater that I am trying to use to load test my MEP-803a . The heater has Black (L1) , Red (L2) , White (L3) and ground wire, In 3 phase 208 settings on the 803 I cannot get 3 legs unless the N is acting as the third leg ( which is barred to the ground still). Is it safe to wire up with the Heaters White (L3) connected to the 803's N ?

Thank you

Kemp

 

[AfghanVeteran2010]

Do you know what the model number the heater is? Sounds like your heater is a 120/240.

 

[Triple Jim]

Doesn't the 803A have four output lugs like the 003A? On the 003A there's L0, which is neutral, then L1, L2, and L3, which are the three phases when in 3-phase mode.

 

[cuad4u]

I just looked at my 803A. Triple Jim is exactly right. L0 is neutral and L1 L2 and L3 are "hot" when in the 3 phase configuration.

 

[Kemp3]

I guess L0 is neutral but there is no setting that I see that uses L1,L2 and L3 simultaneously. I can pull the heater access panel to show you the L1 - Black L2-Red and L3-White that runs through to T1 T2 and T3 if that helps .

-Kemp

 

[kloppk]

Doesn't the 803A have four output lugs like the 003A? On the 003A there's L0, which is neutral, then L1, L2, and L3, which are the three phases when in 3-phase mode.

Yes. 4 Lugs. In 3 phase L1, L2, L3 are the 3 phase outputs and L0 is the Neutral

 

[kloppk]

See page 2-2 in TM 9-6115-642-10 for terminals used in 3 phase.

Also see the electrical diagram on page almost at the end of TM 9-6115-642-24.
It's F0-1 Electrical Schematic and shows L0

 

[Kemp3]

Then I must be misunderstanding the AM/VM switch , this heater should not have a neutral . I guess I will try Black to L1 , Red to L2 and White to L3 and see if any switch settings allow it to work .

 

[AfghanVeteran2010]

Here's a wiring schematic


It sound like there are using the white wire for power as well, you should see where those wires hook up to.

edit: schematic says cable not included.

 

[Suprman]

That heater may just use the 3 legs and a ground. I have one of those it makes a good load bank. It will draw a bit more than listed and the mil generators don't always trip on over current right away. That kind of load can damage a 10kw gen at full draw for too long.

 

[kloppk]

Then I must be misunderstanding the AM/VM switch , this heater should not have a neutral . I guess I will try Black to L1 , Red to L2 and White to L3 and see if any switch settings allow it to work .

It's not the AM/VM switch that sets the 803 to 3 phase mode.
You need to set the output voltage phase selector switch that's on the back wall inside the meter/relay compartment.
Gotta drop the meter panel open to get to it.

 

[m109a2]

Three phase is just what it sounds like, line 1, line 2 and line 3.Al

 

[m109a2]

And ground.

 

[Kemp3]

It's not the AM/VM switch that sets the 803 to 3 phase mode.
You need to set the output voltage phase selector switch that's on the back wall inside the meter/relay compartment.
Gotta drop the meter panel open to get to it.

Sorry I thought the AM/VM switch had something to do with output besides the phase selector. I have the phase selector set to 3 phase 208 , I am now guessing the AM/VM switch really only has to do with the sense gauges on the panel for monitoring.

Thank you

 

[kloppk]

..., I am now guessing the AM/VM switch really only has to do with the sense gauges on the panel for monitoring.

Thank you

Correct

 

[Daybreak]

Here is where you want to make the change, behind the panel.

 

[Kemp3]

With everyone's input I was able to better understand the gen and have it wired correctly. Good news the gen will output 40.6A on all 3 legs @ 208 , bad thing is that is 120% load and protection doesn't kick in . Now I need to come up with a way to vary the load via the 15kw heater to use as a load bank and not be running a constant 120% while testing.

Thank you all for the help

-Kemp

 

[Daybreak]

Howdy,
Check out my load bank thread with the logs which I made while testing.

The military suggest putting a 133% load on the unit for a short duration to ensure it is ready for 100% load 24/7

 

[Triple Jim]

Congratulations on having a great running 803! Putting out 120% of rated load without tripping anything is not a problem you need to fix.

 

[Triple Jim]

(oops, accidental post)