We are looking for either an AC motor or DC-brushless motor that can work under 0-100°C temperature ranges (this is the estimated winding temperature even with a cooling fan, ventilation, and heat sink). The specs include:
-3000 to 6000 rpm (it will be fixed speed, but these are the acceptable ranges; gearing is an option but not optimal)
-10 oz-in torque (very little torque at nominal and starting conditions)
-greater than 10,000 continuous duty life
-less than 2.25" diameter and 4.5" long
-working temp. ranges between 0°C to 100°C (winding temp)
-reversible direction
-24VDC or 220VAC (could use lower VAC w/ step-down transformer; e.g. 115VAC, 24VAC)
The motor is turning a magnet that is coupled to a gear pump. It is pumping fluid that reaches 200°C, but even with heat-isolated coupling, fan cooling, and heat sinking the motor temp is still high.
All AC motors that I've found have been too big. Also, I can't use one with a brake because it dissipates too much heat. We are okay with switching a series capacitor, though.
If we go with a DC-brushless, I would like to find one with integrated electronics to decrease the development time. Unfortunately, this is something I need to get on order within the next couple of days. We have 2 control signals availabe for reversing, starting and stopping.
The reason we are going w/ an AC or DC-brushless is for the long-life. We were using a DC brush motor, and we only got 1000hrs continuous duty out of it. We could use a stepper, but I haven't a small enough driver board to fit into our chassis.
I hope I covered all of the details. I would really appreciate any feedback, as this has become a huge roadblock in the development of our project. Thanks in advance to anyone w/ input!
Todd B.
Electrical Engineer
-3000 to 6000 rpm (it will be fixed speed, but these are the acceptable ranges; gearing is an option but not optimal)
-10 oz-in torque (very little torque at nominal and starting conditions)
-greater than 10,000 continuous duty life
-less than 2.25" diameter and 4.5" long
-working temp. ranges between 0°C to 100°C (winding temp)
-reversible direction
-24VDC or 220VAC (could use lower VAC w/ step-down transformer; e.g. 115VAC, 24VAC)
The motor is turning a magnet that is coupled to a gear pump. It is pumping fluid that reaches 200°C, but even with heat-isolated coupling, fan cooling, and heat sinking the motor temp is still high.
All AC motors that I've found have been too big. Also, I can't use one with a brake because it dissipates too much heat. We are okay with switching a series capacitor, though.
If we go with a DC-brushless, I would like to find one with integrated electronics to decrease the development time. Unfortunately, this is something I need to get on order within the next couple of days. We have 2 control signals availabe for reversing, starting and stopping.
The reason we are going w/ an AC or DC-brushless is for the long-life. We were using a DC brush motor, and we only got 1000hrs continuous duty out of it. We could use a stepper, but I haven't a small enough driver board to fit into our chassis.
I hope I covered all of the details. I would really appreciate any feedback, as this has become a huge roadblock in the development of our project. Thanks in advance to anyone w/ input!
Todd B.
Electrical Engineer
