If you have it working on 240v, why would you ever need to make it work on 120v?

 

Sometimes the projects I use it on doesnt have the L6-30R 250 volt 30 amp power, and only residential power. however, I'm able to use the L6-30p when the project has temporary power and the spider box has the 250 volt 30 amp power.

 

L6-30r to Nema 15/20Ap

A NEMA6 has 2 hot wires going to it, and a ground. A NEMA5 has 1 hot wire, a neutral, and a ground.
If you don't have a neutral you can't do it.
Additionally, the NEMA5-20 recep has to be protected by a 20A max breaker or fuse. If you get an adapter it would be protected by a 30A.

 

Thanks for the info @betelgeuse. Taken from the manual "This drive is rated for 208/230 volt AC line input with jumper set to the 230V position. Rated for 115 Volt AC line with Jumper J1 set to the 115v position."

Couple follow up questions:
1)If the factory NEMA5-20 plug were changed to a NEMA6 and plugged into a 250 V 30 Amp power what would be the risks? The fan that it is operating can draw up to 20.4A.

2) Is this device intended to use a Nema5-20P for both the 115v and 208/230 v?

3) The 20.4A fan trips gfci outlets. I'm trying to find an alternative to the typical 115v power that the fan typically trips. Given the specs do you see any alternatives? Preferably construction site temporary power (portable spider boxes).

 

If the factory NEMA5-20 plug were changed to a NEMA6 and plugged into a 250 V 30 Amp power what would be the risks? The fan that it is operating can draw up to 20.4A.

Forget the what ifs. You need to have separate circuits for each.

 

I doubt that is listed.

 

I believe you are still talking two hots and a ground versus a needed hot/neutral/ground. Apples and pears.

 

I bet that if you put a continuity tester between the ground hole and neutral slot on that adapter, there would be 100% continuity. That would be putting neutral current on the ground, which is not allowed.