z axis jammed 4000 steps July 20, 2015 12:56PM |
Registered: 9 years ago Posts: 17 |
Re: z axis jammed 4000 steps July 20, 2015 01:07PM |
Registered: 10 years ago Posts: 14,672 |
Re: z axis jammed 4000 steps July 20, 2015 01:28PM |
Registered: 9 years ago Posts: 17 |
Re: z axis jammed 4000 steps July 20, 2015 02:26PM |
Registered: 11 years ago Posts: 5,780 |
Re: z axis jammed 4000 steps July 20, 2015 02:46PM |
Registered: 11 years ago Posts: 342 |
Re: z axis jammed 4000 steps July 20, 2015 03:00PM |
Registered: 11 years ago Posts: 5,780 |
Re: z axis jammed 4000 steps July 20, 2015 03:13PM |
Registered: 11 years ago Posts: 342 |
Quote
the_digital_dentist
The voltage rating of the motors is not important except that you want them to be as low as possible because that implies low resistance which also usually implies low inductance. The current determines the torque they produce and the motor driver uses PWM to limit the average current to the set value. Operating from higher than rated voltage increases the speed at which the current rises in the coil. It is perfectly normal to operate steppers from supply voltages 5-20X their rated values.
12V steppers would not work very well with a 12V power supply feeding the drivers.
Re: z axis jammed 4000 steps July 20, 2015 04:00PM |
Registered: 11 years ago Posts: 5,780 |
Re: z axis jammed 4000 steps July 20, 2015 04:18PM |
Registered: 11 years ago Posts: 342 |
Quote
the_digital_dentist
When I said "higher than rated voltage" I was referring to the power supply voltage, not Vref. Vref is used to set the average current through the motor.
The motor's torque spec is based on a specific current. That current results in the maximum allowable motor temperature, usually around 60-65C. So, if you run a motor continuously at its rated current, it will get hot. If you don't need all the torque the motor is capable of delivering, because the load is light, you can reduce the current which in turn reduces the heat.
Part of the definition of the "load" is the mass the motor has to move, how fast it has to accelerate it, how much friction there is, loading due to gravity, etc. All factor in to the required motor torque. If you limit acceleration, have a low friction mechanism, low moving mass, you can use a small motor near its rated torque which will run warm or hot or you can use a larger, high torque motor at reduced current/heat.
Re: z axis jammed 4000 steps July 20, 2015 04:23PM |
Registered: 9 years ago Posts: 17 |
Re: z axis jammed 4000 steps July 20, 2015 04:32PM |
Registered: 11 years ago Posts: 342 |