Big 40 troubles

[kellyranches]

My big 40 is burning up my grinders. How do I check my voltage and what should it be at on high idle ? How would you adjust it down if it's to high ?

[H80N]

My big 40 is burning up my grinders. How do I check my voltage and what should it be at on high idle ? How would you adjust it down if it's to high ?

post your serial number

AND DELETE ALL YOUR DUPLICATE POSTS...

[gnforge]

Gas or diesel ?????

[H80N]

Gas or diesel ?????

His serial number sure would help.....

[kellyranches]

HD690556 gas model and it's a 73 or 74.

[H80N]

HD690556 gas model and it's a 73 or 74.

Here is your manual (really close serial # HD690740 )

https://www.millerwelds.com/files/ow...s/O450_MIL.pdf

[kellyranches]

Ok I read the manual. It says the receptacle should run 55 to 80 amps at idol mine is showing like 137 amps with the idol lock off and running full speed. And idea how to adjust it down ?

[H80N]

See section 4-1 page # 7

[Aeronca41]

Ok I read the manual. It says the receptacle should run 55 to 80 amps at idol mine is showing like 137 amps with the idol lock off and running full speed. And idea how to adjust it down ?

That would be volts, not amps. The ref in the book H80N gives above is key. Have you had a grinder in use while the machine was at low idle? 55-80 Volts is death on motors. Or have you only run them with the machine on weld speed? I believe the NEMA (National Electrical Manufacturers Association) standard is + or - 10%, which would say a good quality NEMA-compliant grinder ought to be able to handle 108-132 volts. Your 137 is a bit high by that standard, and I think NEMA is the broadest case; most utilities shoot for around + or -5%. The usual guidance from the welder techs here is to set engine speed by monitoring the frequency of the outlet power. You can check that with a digital multimeter that has a Hz or Freq capability, or a Kill-A-Watt meter you can get at Home Depot. My guess is that the "Weld" RPM of your machine is a bit high, and you will find the frequency to be above 60 Hz. along with the higher voltage. You will need someone besides me to explain how to adjust the RPM down; I'm not familiar with your welder.

[kellyranches]

No I'm running the grinders at weld speed. They was dewalt grinders too no cheapies. I read you adjust it at the governor to control load speed. But Idk where to adjust it.

[H80N]

No I'm running the grinders at weld speed. They was dewalt grinders too no cheapies. I read you adjust it at the governor to control load speed. But Idk where to adjust it.

I think Aeronca41 is on the correct track with looking at your AUX 120vac Frequency..... too low a freq can burn up grinders too...

[Aeronca41]

I think Aeronca41 is on the correct track with looking at your AUX 120vac Frequency..... too low a freq can burn up grinders too...

...and if the voltage is high, unless there is an adjustment for voltage--I don't have time to look at the diagram right now--it's likely the freq is also high. Freq is absolutely the best check for engine speed. Get yourself a meter that will measure freq and go from there. The Kill-A-Watt meter is really great and not very expensive. I have more meters, oscilloscopes, and other electronics test gear than any reasonable person needs, but I bought a Kill-A-Watt because it's just so easy to use-just plug it in and push the button for voltage or frequency. You can also use it to see how much power various things in your house are using since it also reads kilowatts. Anything up to 15 amps. Maybe Duaneb55 or Cruizer will see this, they would both know how to set the engine speed, and I think their direction will include using a freq meter.

[H80N]

...and if the voltage is high, unless there is an adjustment for voltage--I don't have time to look at the diagram right now--it's likely the freq is also high. Freq is absolutely the best check for engine speed. Get yourself a meter that will measure freq and go from there. The Kill-A-Watt meter is really great and not very expensive. I have more meters, oscilloscopes, and other electronics test gear than any reasonable person needs, but I bought a Kill-A-Watt because it's just so easy to use-just plug it in and push the button for voltage or frequency. You can also use it to see how much power various things in your house are using since it also reads kilowatts. Anything up to 15 amps. Maybe Duaneb55 or Cruizer will see this, they would both know how to set the engine speed, and I think their direction will include using a freq meter.

Sound Advice...

Ok I read the manual. It says the receptacle should run 55 to 80 amps at idol mine is showing like 137 amps with the idol lock off and running full speed. And idea how to adjust it down ?

Cruizer's wisdom and experience would sure be welcome here..

As I read the manual..... the 55-80 is Open Circuit Voltage for welding output

NOT Amperage related to the AUX AC outlet.... that should supply 3Kw of 120VAC @ 60Hz with the machine running at welding speed..

First...measure voltage and frequency at the outlet.... that will tell us a lot about if the governor needs adjustment

see Section 2 Page # 5

https://www.millerwelds.com/files/ow...s/O450_MIL.pdf



BTW how does it weld...??

[gnforge]

I looked up some notes I kept from old post cruiser had on this. Can probably find them if search long enough. But I'll be close. Set weld rpm. With no load. Low rpm diesel i.e. 1800 area. Set to 60.5 - 61hz. <br />
Set small gassers to 62.5 hz area <br />
And I'm guessing yours, med. gas and diesel high rpm. I.e. 3600 rpm area set to 61.0 - 62hz area. <br />
Set high or weld rpm to this hz setting with no load and should be fine.

[Aeronca41]

Good stuff. According to the manual H80N posted, this is an 1800 RPM machine.