MC33035DW Motor Controller

Thread Starter

bluestreakG1

Joined Aug 22, 2017
19
Hi. Can anyone help me with my design? I want to replace a high-power motor (MFA0114) with a low one (MFA0300). I need a pressure output at 70cmH20 (page 3 of Air-MFA0300). To get that I need to reduce the power. Can anyone familiar with PWM controller to advice me?

I attach the motor and MC33035W motor controller datasheet and the schematic diagram of my driver board.

Thank you.
 

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shortbus

Joined Sep 30, 2009
8,593
First off glad to see some one else referencing the old MC33035 chip, besides me. But a concern is does the motor in that fan work with it? Do you have other data sheets on the motor/fan unit? The MC33035 is meant for a BLDC motor that uses Hall sensors, most modern BLDC motors have gone away from their use, and now sense rotor position electronically not using Hall sensors.

If your motor/fan is one of the more modern ones(which I'm guessing it will be) you will probably need what they call an ESC (electronic speed controller). They are made for the BLDC motors that don't use Hall sensors.
 

Thread Starter

bluestreakG1

Joined Aug 22, 2017
19
The speed is controlled by a microcontroller to pin 11 of MC33035DW. Is changing the resistance value of current limit resistor at R1 will limit the current and power to the motor?
 

shortbus

Joined Sep 30, 2009
8,593
The speed is controlled by a microcontroller to pin 11 of MC33035DW.
You seem to have missed my point. Does your motor use Hall effect sensors? Older BLDC motors did, to find the position of the rotor. Newer ones don't have or use Hall sensors.

What is the microcontroller going to read/sense to give the signal to pin 11? Modern say from the last 5 -10 years(don't know exactly) use a totally different way of finding the rotors position, again I don't completely understand how. But do know it is built into the BLDC driver module. Maybe you know how the rotor position is found but I don't. Rotor position is needed though, to tell the controller when to switch the coils on and off to make the motor work.

After saying that, there if your motor has Hall sensors, a companion chip to the MC33035, it's the MC33039. It senses the RPM of the motor from the Hall sensors and controls the motor speed, keeping at a certain RPM if there is a load. Here is an application note that explains how the two chips work in tandem.
https://www.onsemi.com/pub/Collateral/AN1046-D.PDF
 

MaxHeadRoom

Joined Jul 18, 2013
23,144
Current BLDC servo motors still use sensors for feedback, but these are now placed next to the encoder tracks. Rather than descrete devices
The MC33030 - MC33035 was originally intended as a servo motor driver.
See commutation by Renco.
Max.
 

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MaxHeadRoom

Joined Jul 18, 2013
23,144
The speed is controlled by a microcontroller to pin 11 of MC33035DW. Is changing the resistance value of current limit resistor at R1 will limit the current and power to the motor?
The voltage on Pjn 11 decides the RPM of the motor.
Presumably changing the value of the divider R42 - R7 would reduce or increase the motor RPM.
.
 

shortbus

Joined Sep 30, 2009
8,593
Current BLDC servo motors still use sensors for feedback, but these are now placed next to the encoder tracks. Rather than descrete devices
But I think his simple motor is more like a drone motor than it is a servo motor,sinse it's only a fan. It's my understanding that a drone type motor/ESC uses a form of reluctance measurement on the unpowered coil to find rotor position for the commutation. But like I said earlier I'm not sure.
 
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