5HP reactors, 3/4HP motor

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tkb

Senior Member
Location
MA
Why would you need a line and load reactor? I have only used line reactors.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
So I still don't get the issue of the reversing starter if you have a VFD, because the VFD can be told to reverse the motor very simply, no contactors needed.

Are you replacing the VFD with a reversing starter and want to know if leaving the reactors in place is OK? If so, yes, but you will waste a little energy through the reactors.

Oh wait, are you wanting to use the over sized VFD instead of a reversing starter and want to know if having the line and load reactors on a smaller motor is OK? Then yes again, but same issue.

Generaly it were a vector drive, you couldn't use a 5HP drive on a 3/4HP motor because it's too small; most vector drives will have a lower limit of 50% of the drive rating, because for the vector to work it needs accurate current information and below 50% rating the measurement error gets in the way. But the PF4 is not a vector drive, so it doesn't care.
 
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Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
So I still don't get the issue of the reversing starter if you have a VFD, because the VFD can be told to reverse the motor very simply, no contactors needed.

Are you replacing the VFD with a reversing starter and want to know if leaving the reactors in place is OK? If so, yes, but you will waste a little energy through the reactors.

Oh wait, are you wanting to use the over sized VFD instead of a reversing starter and want to know if having the line and load reactors on a smaller motor is OK? Then yes again, but same issue.

Generaly it were a vector drive, you couldn't use a 5HP drive on a 3/4HP motor because it's too small; most vector drives will have a lower limit of 50% of the drive rating, because for the vector to work it needs accurate current information and below 50% rating the measurement error gets in the way. But the PF4 is not a vector drive, so it doesn't care.

I thought I was clear, but I guess not. My help look at me with glazed eyes often enough so I should know better.

Wasting a bit of energy doesn't bother me and I don't think there will be a reflective wave problem @ 15' to the motor but if it won't hurt, I would just leave it in place.
 
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