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vnh5019
#1
My homebrew H-bridge controller works fine with a linear actuator.

I also have a Polulu VNH5019 board which I like for its small size.
I read that people have successfully used it with the standard motor.ino and  #define VNH2SP30 // 
The problem is my actuator does not move very fast, even if I set the max servo speed to 100%.
The PWM sound from the actuator is also different.

i assume the PWM frequency from the nano determines the servo speed.
Does any one have an idea why the actuator moves so slow?

Without load the actuator draws less than 1Amp and the power supply is a 13,2V 30A unit.
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#2
the pwm frequency doesn't normally determine the speed. The speed is determined by the duty cycle. The exception is that as the frequency is increased, the maximum speed is decreased because of increased time switching. motor.ino gets around this by switching to a very low frequency once you reach maximum duty cycle, and because the duty cycle is mostly on, the current remains continuous and there is no noise generated, but the motor can achieve nearly the same output as a direct dc connection.

Some switching is needed at full duty cycle to refresh the bootstrap capacitors which charge the high-side mosfets.
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#3
(2020-08-22, 02:37 AM)seandepagnier Wrote: the pwm frequency doesn't normally determine the speed.   The speed is determined by the duty cycle.   The exception is that as the frequency is increased, the maximum speed is decreased because of increased time switching.   motor.ino gets around this by switching to a very low frequency once you reach maximum duty cycle, and because the duty cycle is mostly on, the current remains continuous and there is no noise generated, but the motor can achieve nearly the same output as a direct dc connection.

Some switching is needed at full duty cycle to refresh the bootstrap capacitors which charge the high-side mosfets.

Thanks, I was confusing FM and PWM.
I took the board back home to the workbench to hook up my scope.
The wave form looks weird with low output and distorted pulses.
Probably another faulty board Sad 
At least my H bridge works.
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