So to start the story... I have a new instillation of a water pump. They had me on startup limit the max freq. to 42hz on VFD. I did so without even asking why.
After running the pump it does about 1700 to 1800 gpm depending on the head pressure. At 42hz and 29amps (rated 26amps) 30.5 trip. But they want more flow.
They have a restrictor plate on the line...and some discussion started about how to increase the flow.
Engineer says.. just remove the restrictor plate. problems solved.. well needless to say I tried to explain that "work" is work. If you remove the plate the current will go down..agreed.. but the flow will decrease. He says.. then increase the max frequency... well to my dismay he could not comprehend that this would increase flow..and increase current to the same (or close to) the overload.
oh and yes the pump is spinning the right direction..lol
After running the pump it does about 1700 to 1800 gpm depending on the head pressure. At 42hz and 29amps (rated 26amps) 30.5 trip. But they want more flow.
They have a restrictor plate on the line...and some discussion started about how to increase the flow.
Engineer says.. just remove the restrictor plate. problems solved.. well needless to say I tried to explain that "work" is work. If you remove the plate the current will go down..agreed.. but the flow will decrease. He says.. then increase the max frequency... well to my dismay he could not comprehend that this would increase flow..and increase current to the same (or close to) the overload.
oh and yes the pump is spinning the right direction..lol