I have been asked to quote a few jobs lately that have conveyors with 2~4 motors running the same section. These are explosion proof motors and the size is the problem for where they are physically located. We can only put a 10 hp motors in there. It is just tight.
The drives change from customer to customer. I try to use a baseline drive like a AB PF70 ,ABB ACS550, Baldor VS1, so just about anybody's drives. Siemens will be soon I am sure.
My question is how do you handle load sharing? I was thinking about having all of the motors running in Sensorless vector and speed regulating the first one. The rest of them would run in torque regulation mode. The torque signal would be the torque feedback of the main motor that is running in speed mode.
A few questions with this method.
1. Am I stupid for thinking of such a simple approach?
2. Lag on startup. From the time the main drive gets a speed ref and replies with the torque feedback it will be in overload condition for a short time. Right? Or is that such a short time that it will not matter.
3. The speed regulation is not tight at all. A V/H drive has done this with the correct room so we can get the right sized motor in there. Would I have a huge fluctuation in the speed. I don't think so because of the sensorless vector mode.
Any pointers?
The drives change from customer to customer. I try to use a baseline drive like a AB PF70 ,ABB ACS550, Baldor VS1, so just about anybody's drives. Siemens will be soon I am sure.
My question is how do you handle load sharing? I was thinking about having all of the motors running in Sensorless vector and speed regulating the first one. The rest of them would run in torque regulation mode. The torque signal would be the torque feedback of the main motor that is running in speed mode.
A few questions with this method.
1. Am I stupid for thinking of such a simple approach?
2. Lag on startup. From the time the main drive gets a speed ref and replies with the torque feedback it will be in overload condition for a short time. Right? Or is that such a short time that it will not matter.
3. The speed regulation is not tight at all. A V/H drive has done this with the correct room so we can get the right sized motor in there. Would I have a huge fluctuation in the speed. I don't think so because of the sensorless vector mode.
Any pointers?