HB 25 motor controller fault LED
pmolina
Posts: 1
Hi!
We are having a problem with the HB25 motor controllers. It would be greatly appreciated if someone can provide some hints as per what is actually happening.
We are trying to drive a large 6-wheel skid steering chassis (transmission using chains connected to central wheels) using 4 motors (2 motors for left side and 2 motors for right side). Each pair of motors is connected to a 1:32 gearbox and the output directly into the main shaft.
The motors are standard CIM motors from First Robotics
We have each motor connected to a HB25. We have seen other similar vehicles using 40A motor controllers to drive 2 motors, so we expected that having 25A for each motor will be enough.
However, the HB25 fault LED comes on whenever we are making turns or putting torque to the wheels (We basically hug the wheels slightly and see that the motor controllers fault.)
From the datasheet, I understand that there are 3 fault modes (over current, over voltage and over temperature)
Temperature is not a problem as the fans are working normally and the HBridge is not hot at any time.
The HB25 motor controllers have a continuous 25A rating and 35A surge.
We know for sure that we are not reaching the surge current because we have placed 15A fuses on the motor controllers and they do not trip, but the motor controllers faults.
It is not the battery (maybe requesting too much current and voltage drops below 6v) because we have replaced it with a big deep-cycle 100Ah marine battery that is fully charged and it still faults.
It is not the PWM signal since we have used different "R/C" PWM signals (from our micro-controller or from a small servo testing unit), and the motor controllers still fault
We do not understand what is going :blank:. We do not want to just buy motor controllers and see that the problem is still there. :frown:
It would be greatly appreciated if someone can shed some light into this
Thanks in advance!
Pablo
We are having a problem with the HB25 motor controllers. It would be greatly appreciated if someone can provide some hints as per what is actually happening.
We are trying to drive a large 6-wheel skid steering chassis (transmission using chains connected to central wheels) using 4 motors (2 motors for left side and 2 motors for right side). Each pair of motors is connected to a 1:32 gearbox and the output directly into the main shaft.
The motors are standard CIM motors from First Robotics
We have each motor connected to a HB25. We have seen other similar vehicles using 40A motor controllers to drive 2 motors, so we expected that having 25A for each motor will be enough.
However, the HB25 fault LED comes on whenever we are making turns or putting torque to the wheels (We basically hug the wheels slightly and see that the motor controllers fault.)
From the datasheet, I understand that there are 3 fault modes (over current, over voltage and over temperature)
Temperature is not a problem as the fans are working normally and the HBridge is not hot at any time.
The HB25 motor controllers have a continuous 25A rating and 35A surge.
We know for sure that we are not reaching the surge current because we have placed 15A fuses on the motor controllers and they do not trip, but the motor controllers faults.
It is not the battery (maybe requesting too much current and voltage drops below 6v) because we have replaced it with a big deep-cycle 100Ah marine battery that is fully charged and it still faults.
It is not the PWM signal since we have used different "R/C" PWM signals (from our micro-controller or from a small servo testing unit), and the motor controllers still fault
We do not understand what is going :blank:. We do not want to just buy motor controllers and see that the problem is still there. :frown:
It would be greatly appreciated if someone can shed some light into this
Thanks in advance!
Pablo
Comments
The fact you haven't blown the fuse is not a valid indicator since the fuse can easily supply a large amount of current for quite awhile before blowing.
Take the current readings and get back to us. There may be some technical ways out of the situation.
Cheers,
How big/heavy are the wheels? How much resistance is in the drive train? Are the chains too tight?
Typically each CIM motor is driven by a 40 amp controller.
I agree with stamptrol that you are probably drawing more current than you think.
Rich H