As "suggested" above: feed the 4amp motor with a separate circuit. You are required to balance the loads and since you will have to install a Grounded Conductor (in this case a Neutral) to run the small motor, it is just as easy to pull the additional Non-Grounded ("Hot") conductor leg. This 4 amp motor will not be fused correctly if you do not put it on a separate circuit from the 3-phase. Then you can make it a Weather Proof cord and Plug connected piece of equipment, and this 120V circuit will be useful because you can install a GFCI Receptacle to supply the required outlet for maintenace of the roof-top equipment.
[This message has been edited by DJF (edited 05-23-2003).]
