ECN Forum Forums General Topics of the Trade General Discussion Area Schedule for on load trial

Dear Friends,
Can somebody throw light on the following.

For Standby (Emergency) Diesel engine set and ATS , is their any compulsory time schedule like weekly , monthly etc for load test to keep it 'work" worthy or is it just a matter of one's convenience ??
We have at our site CATERPILLAR make genset of capacities ranging between 250 to 2000 KVA.,for which normally we do a weekly trial run without load for about 5 to 10 minutes( not thro ATS).