SmartDrive40 Motor and PSU

[Nolebrain]

Greetings,

This is my first post here! I had some general questions about my motor and power supply being used with the SmartDrive40.

I am using a brushed DC motor with a 24V power supply. Listed below are the specs of the motor.

Peak Horsepower: 2.1
Stall Torque (oz-in): 1500
Efficiency: 79%
Voltage*: 24*
No-Load RPM: 5700
Pounds: 5.9
Peak Efficiency (PE): 79%
RPM at PE: 5100
Torque at PE (oz-in): 145
Horsepower at PE: 0.75 HP
Current at PE: 29 Amps
HP Range for 75%+ Efficiency: 0.4 to 1.3

Performance Chart:
http://www.ampflow.com/E30-400_Chart.png

My concern is that this drive will be able to handle long operation of this motor. The application is a low speed (180-750 RPM) as are the torque requirements. The PSU is only rated at 8.8 A, so over-current should not be a problem.
I realize this motor is designed for high speed applications, but it was the only one I had laying around.

In the manual, I read:



Since I am using a industrial PSU, do I need to connect a battery in parallel? The PSU is a 24Volt 8.5amp Switching Power Supply
100-240 VAC.

Hopefully you guys can provide some insight on this design, thanks in advance. Any help is appreciated!

[waiweng83]

I'm sorry I can't see your image properly.

BTW, to reply your question, yes, you have to connect a 24V battery (2x12V in series) to your power supply. It's recommended to use the SLA battery.

This is because MDS40A is a regenerative motor driver. Which means when the motor is braking or slowing down, the current generated by the motor will flow back to the power source to charge the battery. If your switching power supply cannot absorb this current, it will cause overvoltage and the power supply may enter protection mode and shut down itself. Or worse, it may spoil the power supply and MDS40A all together.

[Nolebrain]

Ah that makes sense! I would want to use a sealed lead acid battery with the same voltage (24v) of the power supply right?

I've never directly wired a PSU to a battery before, are there any other components or just the battery in parallel with the supply.
It would seem like if the power supply was left on continuously that it would overcharge the SLA battery?

Sorry for such fundamental questions. Any help is appreciated!

[waiweng83]

Don't worry. The 24V SLA battery will only be fully charged at around 28V. As long as the voltage of your power supply doesn't exceed that, then you will be safe. Just make sure the polarity of the battery is correct (Power supply + connect to battery +, power supply - connect to battery -).

[Nolebrain]

Sounds good, I measured my power supply voltage at 23.95. Since this is much lower than the maximum battery voltage will it never fully charge the battery? Just want to make sure I'm not going to destroy my battery.

[Nolebrain]

Alright, I finally received my SmartDrive and wired it up to be controlled via PWM by Arduino Uno. I set my DIP switches (10010001) for PWM Single Channel, Sign-Magnitude mode. My arduino is sending an analog PWM signal to the IN1 pin and a digital 5V signal to IN2. When I power up the drive the error light blinks twice indicating an Input Error. I had verified the PWM signal with my scope (3.15V with +Duty = 66.7 % / -Duty=33.3 %, Freq = 490.2 Hz).

I was wondering what I might be missing here. My motor is not attached, my multimeter is attached to the motor terminal block to measure the voltage supplied by the drive for various input signals. But when I run the system my meter reads 0V on A and B. Any help is appreciated, first time using Cytron drives, hopefully I just set the DIP switches incorrectly!

[robosang]

A photo of the hardware setup would be helpful.

[waiweng83]

Please refer to page 24 of the User's Manual:

NOTE: The Analog/PWM signal to stop the motor (2.5V if Sign-Magnitude mode is off, 0V otherwise) must be available when the SmartDrive40 is turned on. Else, the driver will show Input Error until the correct signal is available.

which means right after power up the system, your PWM signal must be 0 for a while (300ms should be enough), then only you can change the value to your desire value. This is to prevent the motor start up accidentally when power on.