anatomist_noelectrons:
Hi,
I have a Life Fitness treadmill motor (90v DC, 20AMP, 4000RPM, 2 HP, Continuous Duty) along with MC-60 control board. I am looking for ways to speed control this motor with Arduino. The control pins for this board seem to be different from Sole Fitness control board, which seems to be hacked to come up with an interface (Treadmill Project - Project Guidance - Arduino Forum).
In addition to exploring the interfacing of Arduino with MC-60 control board, I am also exploring building a programmable power supply to the motor so that I can replace the complex control board.
Most critical challenge seems to be bridging Arduino outputs (5V and <100mA) and motor inputs (90V and 20A). My ideas to replace the board are revolving around these options:
(a) AC power supply (US: 120V 60HZ) --> Bridge Rectifier + Capacitor (~ 100v-120v DC) --> High Current DC Relay Switch (to simulate Pulses via on/off) programmable with Arduino --> DC Motor
(b) AC power supply (US: 120V 60HZ) --> SCR + Digital Potentiometer programmable with Arduino --> Bridge Rectifier --> DC Motor
Are these ideas feasible? Are there any other ways to programmatically control a big DC motor (treadmill motor or other DC motors which handle similar torque)? All the projects and ideas I found in my searches are to control tiny DC motors.
Any information or help is appreciated.
Thanks in advance.
the simple flow chart is controller, ie: arduino.
this puts out TTL values.
a motor driver.
this can be 600 volts, 100 amps, whatever it is
it can be AC output, DC output, PWM... whaterver
the motor.
there are a lot of motor types, your driver needs to be able to control that motor.
the existing driver can easily be fed control signals. but, you need to do a bit of research on a few things.
#1) what is the voltage needed for the speed control
1a ) is it AC or DC
#2) what settings do you need to make on that controller. there are max and min AMP settings. low speed cut off, ramp times, and minimum start values.
The typical driver is really simple, but has limited features. it needs to get above 50% power in order to start the motor. some need to start at or near full speed. only then can you back it off to control at lower speeds.
also, there are basically two types of loads, a centrifugal load or variable torque. like a flywheel.
you can spin a flywheel on a 100 HP motor, by hand. but not fast. many machine tools allow you to spin by hand, but then need high power to do any work.
constant torque. these require full power on the first revolution. like a compressor or crusher.
application is the key. your car cannot be started under a full load. you start the engine, then add load slowly.
a feedback would be recommended for your load. the treadmill has a magnet in the drive pulley and a hall sensor to count RPM.
if you want to get away from the driver you listed and build your own, you are well out of the hobby arena and into a high power, high voltage area that most of us do not discuss on these hobbiest boards, something about widows and lawers seems to silence the advise. so, if you want to replace that, I would recomend that you do some research and buy a driver that is rated for that motor and for your project.
as a note, if you go that route, a brief, fun project to dabble with first is a battery powered ESP8288 with a mercury switch to the battery.
when the mercury switch makes contact, the ESP8266 starts and all it does is to send out a signal to peoples cell phones.
you attatch this to your belt.
and when your friends and family get a text "this is my automated tilt sensor alarm. if you are getting this, please find my body laying on the floor of my workshop. "