In one of the gas turbine units, we see that when one ventilation fan is running (centrifugal type), the load (amperes) are ok i.e. 120 amps as compared to other ventilation fans in other units.

When auxiliary ventilation fan starts running, the load (ampere) is dropped for both ventilation fans i.e. both are running at 65-90 amps. when only one runs amp is OK.

When both runs at same time the ampere both take are approx.. 65-90 amps..

Where as ventilation fans in other units are taking constant load (amps) whether both running at same time or one running at a time. i.e 120 amps.

Would like to ask the role of suction pressure or discharge pressure of the ventilation fans. do they play any role.

Since we saw, the ventilation inlet damper (co2 damper/ fire damper) whatever we call - after the ventilation fans is partially closed . i.e not fully open. It's a spring type damper.

Can this be the reason? tried manually to open but was not able. how can we reset the damper? Or the damper should open by itself with ventilation air pressure/flow.

but i believe there is a gravity damper before this damper / or just after ventilation fan which works fine.

So, please advise what all possible reasons could effect the load drop of the ventilation fans when running in parallel.

& how to reset the co2 damper/ fire damper/ inlet ventilation damper.

Thanks and regards,
ARF

 

the current draw is a function of the discharge damper because a partial closed damper reduces the air flow (fan discharge pressure also goes up according to the fan curves).

 

The current drawn by a fan motor is a function of the air being moved by the fan. Without being able to see the P&ID and understand the placements of the dampers (gravity- operate and/or latched) we can't comment with any degree of certainty. We don't even know if the configurations of the fans on all the units are the same.

But, it doesn't have anything to do with being installed on a gas turbine application; it's strictly a function of air flow (movement).

 

Arf... I suggest you search the Control.Com Archives for the Cube-Rule associated with Fans!

Regards, Phil Corso