Bought new petrol generator (240V/650Watts) to power 2 lights for filming. The lights are 240v/300watts each. When connected, the one light fused after a few minutes closely followed by the second light, Any ideas please, thanks, Tom.

Best we can offer is to measure the voltage output of the genset to verify the voltage is 240 volts. And verify the lamps are rated for 240 volts, find the specs on the lamp to learn what the +/- tolerance is.

My guess is the lamps are quartz halogen, which undervoltage will extend the life of the lamp greatly, and overvoltage will shorten the life quickly.