I'm doing an art project and a team member is bringing their vacuum pump over to my house for some work on this project. He tells me it is 220v with a 3 prong plug that has an L shaped prong and 2 straight prongs at an angle. Here is a picture http://tinyurl.com/ct4bj
It's the one with the grey wire.
In my home I have a dryer outlet that was made for a 4 prong plug. One hole is round, 2 straight prongs up and down, and one L shaped.
Question: Can I build an adapter so we can plug in his vacuum pump? This is a one time thing and I really want to have this work if at all possible.
I can buy a 3 prong receptacle to match the plug on the pump, and a 4-prong plug that will match my receptacle, I just need to know how to connect the wires.