Tagged Questions
3
votes
3answers
104 views
Does the frequency of a PWM signal have to be constant for a DC motor/fan speed control?
All PWM control systems I have seen for DC motor/fan speed control used a constant frequency. Is this really necessary in all cases?
How would the motor current have to be calculated for a PWM ...
1
vote
1answer
129 views
Speed control for high power DC brushed motor
I am going to drive and bi-directionally control the speed of some 12V/24V, 100W to 300W DC brushed motors.
I have some experience in controlling small DC motors (6V/9V/12V, 0.5A to 2A) with PWM ...
-1
votes
5answers
305 views
how to automatically reverse the direction of a stopped gear motor and restart 12 hours later
The reversible gear motor needs to turn on @ 6:00 am pull a object 12 inches and shut off. Twelve hours later the gear motor needs to turn on and reverse the direction and place the object back in ...
3
votes
3answers
117 views
How to syncronize two motors with one pot?
I am trying to synchronize two dc motors with their own controllers. The controllers are name brand and use a 10k pot to control the speed. I have a duel 10k pot and would like to be able to "trim" ...
3
votes
1answer
199 views
Choosing relay to operate water pump
Based on my research so far, I've concluded that a relatively low-cost, yet reasonably reliable way to control operation (on/off) a motorized water pump, is a well spec'd EM-relay with flyback diode. ...
2
votes
1answer
155 views
What is the mathematical relationship between MOSFET switching frequency (motor speed control) and motor speed in rpm?
What is the mathematical relationship between the switching frequency of MOSFET in a three phase motor controller (induction motor and BLDC motor) and the speed in rpm of the motor shaft?
1
vote
1answer
215 views
MOSFET relay connections to control a 3V motor
I need to turn a 1A, 3V motor on and off with a touch switch. I bought Omron 653-G3VM-61-AR and quickly smoked it. I had the battery + connected thru a 300 Ohm resistor to the touch switch (to get ...
2
votes
2answers
248 views
Motor Soft Starter
I am demonstrating a soft-starter for a technical report, and I am having trouble finding the correct motor and power source.
I want to use SCRs in a reverse-parallel configuration to limit the ...
0
votes
3answers
615 views
Can a motor driver for 5V be used for a 24V motor?
I’m controlling a 5V motor with Arduino but need more torque which means a more powerful motor. Here is my scheme. (I took it form a tutorial):
Here Arduino is controlling a 5V unipolar stepper ...
0
votes
2answers
115 views
What type of electric motor drive can be used for keeping a load at specific heights? [closed]
We are planning to adjust the level of a load (around 50 kg) by using an electrical motor. Now we are using a hand crank and we want to get rid of this manual process.
For example we want to ...
6
votes
3answers
4k views
Control differences between ac induction motor and brushless dc motor?
I have a fairly solid background in industrial AC motor control (soft starters, VFDs, etc.) but something that I'm certainly NOT well versed in is brushless DC motors... the type found in every hard ...
3
votes
1answer
223 views
Regulate DC-Pump throughput
Does anybody know whether it is possible to easily regulate the throughput of a DC water pump? E.g. one you would use for your pond or indoor fountain.
I would like to avoid lowering the duty cycle ...
3
votes
3answers
981 views
Using a motor to open doors
I have made a wooden case to hold both my Xbox 360 and my PS3. It's as wide as both consoles laid down next to each other and as high as the console. it has 2 doors on the front, one for each console. ...
1
vote
1answer
274 views
Soft Starter Sizing for No Load Testing of Motors
Don't know if this would be more appropriate on any other stackexchange site but my question is :
How do you evaluate the sizing of a softstarter for no-load testing of an induction motor ?? For ...
1
vote
2answers
1k views
What determines the speed of a brushless DC motor
When driving a brushless DC motor, which parameters control the speed. Is it the current in the windings, the voltage, or both? What determines the maximum speed? If you drive the windings with ...
3
votes
2answers
2k views
AC fan speed control
I use this fan to cool my room, but sometimes it is too fast and I have to frequenctly turn it on and off to keep normal temperature. Maybe it is possible to reduce the speed by connecting a resistor ...
4
votes
3answers
509 views
How is precise control over motor as in Segway achieved?
When I read about Segway I always wonder how such precise control over the wheel motors can be achieved.
I mean if the rider wants to go one foot forward, then one foot back, he leans forward, the ...
3
votes
4answers
2k views
Controlling water pump speed
How can you control the speed of an AC water pump? In particular this one.
My guess is that PWM won't work on an AC motor? I've heard that controlling the voltage will change it's speed...is this ...
