Mep-805b 480V operation

[aricannon]

So the placard states that 3 phase adjustment range is 60hz 395-480v. So ....I ass u me.... that means i can run a 480v Y load using this machine?

When I fire it up and begin adjusting voltage up, I get an "overvoltage" message at about 457v. The bar graph stops at 430v. But it will climb to 480v and beyond. This gives me a 277v L1 to L0 voltage. 480v L1 to L2 as measured.

Should (can) I disregard the overvoltage warning. Again specs state adjustable range of 395-480. Will this compromise the machine in anyway?

I am looking to use it to power a 3○ robotic demolition machine.

Thank you

 

[aricannon]

Any opinions on this?

 

[porkysplace]

Any opinions on this?

Since very few people use 480v on here it will more than 10 hours to get a answer , there are some generator guru's on here but they don't log on every day .

If your in a big hurry you may want to contact Green Mountain Generators .

 

[aricannon]

Hey thanks for the input. I am in need of getting this in service. I am waiting to see if I should pull the trigger on an isolation transformer or not.

 

[DieselAddict]

To run the higher voltage means you are running the exciter coils harder (I'm not a fan of that). You are stressing the insulation a little more (not that big a deal). Also your overload protection will be out of whack (not good).

If it were me and it was needed for a short term emergency I would say - go for it. If this is something you intend to run as normal then you need a transformer.

 

[aricannon]

Thank you for that reply. Much appreciated!

 

[155mm]

You will not get 480v, you will get 416v. You can get 240v per leg x3, but with 3ph your voltage will be off 1/3, so leg to leg you only get 416, not 480

 

[155mm]

 

[aricannon]

First I already ordered a 30kva transformer today after reading DieselAddict's response.

However 155mm. I appreciate your response. But I van tell you affirmatively that L-L0 was 277v wye and L-L was in fact 480v wye. This was metered by my genset and also verified by my Fluke 185 on the output lugs of the genset. So im not certain why you can only get 416. My 805B is a 2012 L3 unit. Thanks though.

 

[155mm]

Oh, I dont disagree that the voltage regulator will adjust to 480v, but the set was not designed for 480 L-L. I would also check your demo setup and see what 277 L-0 will do and if you motors are rated for it.

 

[aricannon]

155mm...Yes sir that was the objective behind my question. I wondered the genset's ability to handle that increase in voltage in a stable manner long-term without compromising the health of generator. I think I understand now that the answer is no. I really appreciate your input and aid.

This still leaves me questioning the other placard on the genset. It states 60hz 416v 3ph with adjustable range from 395v to 480v. So...why does it allow and specify a voltage range, if that range of voltages would bring it into a dangerous operating range? Even the software states overvoltage around 457v.

That said...I also did observe noticable Voltage flucuations and appearance of instability when running that high. So I dont argue at all the statements made......just the placard should not state an unusable range.....should it?

Thanks again

 

[DieselAddict]

I think at issue is the difference between rating and capability. The rating is 416v. If you are going to operate it per norms for power delivery the voltage needs to be within 5% of the rating. That would certainly exclude it from being run at 460-480 range except in unusual cercumstances. That is why I stated before that if you had to push it for an emergency then go ahead. Even then I would run it on the low side meaning not exceeding 460v.

Since you ordered the transformer you'll be in good shape. The generator will be happy which should keep you happy.

 

[aricannon]

That makes sense DieselAddict and I do remember you saying it would be ok for emergency.

Two week lead time on the transformer. Then I'll be up and running. Sure would've been nice not to have to pay for that thing, but as you said....I will be happy I did.

Thank you for the guidance. It was much appreciated.