ant1dp
Active Member
Loving building parts for my superbike
Posts: 17
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Post by ant1dp on Apr 18, 2024 9:49:03 GMT
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ant1dp
Active Member
Loving building parts for my superbike
Posts: 17
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Post by ant1dp on Apr 18, 2024 10:17:19 GMT
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Post by chris vine on Apr 18, 2024 17:25:20 GMT
An excellent recycling plan!
I am not the electrical engineer on this forum, however I wonder if matching the output of the controller so closely to the demand from the motor is the correct thing to do.
For me, I would be looking for a margin there. Maybe as much as x2.
If they use the same quality control on the controller as they do on the "English" for the description, I wouldn't leave it switched on when you leave the workshop!!!
Chris.
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ant1dp
Active Member
Loving building parts for my superbike
Posts: 17
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Post by ant1dp on Apr 18, 2024 18:52:17 GMT
Hi Chris
well ive watched a few vids on powering these and the experts defo match the voltage, as for watts or amps actually this is the largest output PWM I could find, also as its a motor controller I dont have to turn it up to full speed.
Dazecars.com who does the treadmill channel mentions a few ways to power these and yes I agree I wouldnt leave any switched on. When the last motor controller blew on my treadmill it applied full power through the treadmill, I didnt know because it was earthed but I hired a treadmill tech (rip off for £300 cos they almost never repair controllers) but the techy guy got a right whollop and burned a fair chunk out of his screwdriver. He said if the screwdriver wasnt sheilded he could of died, so I guess he earned his money.
Ive seen vids on people buying old treadmills to frankinstein the parts to put in mini lathes and while the controllers off treadmills look odd next to the lathe they run really well apparently.
My shed doesnt have a lot of room for a £1000 vertical bandsaw even if I could afford one but the 120w motor on mine is next to useless unless cutting 2mm plastic, I want to cut 5mm alloy and 10mm heavy engineering plastics like nylon and my little saw has the blade options just not the power. I also really enjoy this stuff, I spend more time making parts to work with than anything like furniture or bike parts.
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Post by chris vine on Apr 18, 2024 21:07:15 GMT
I was thinking more about the capacity to provide the current being a bit marginal.
If you don't load up the motor too much, it might be fine.
Just watch out for DC at these sorts of voltages!
Chris.
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ant1dp
Active Member
Loving building parts for my superbike
Posts: 17
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Post by ant1dp on Apr 18, 2024 23:22:14 GMT
So my choice was all wrong, I need a 10,000W SCR motor controller, a Bridge rectifier to change AC to DC and a vented metal box to put all the bits inside and earth. If I buy the most expensive SCR and Bridge its still cheaper than that first PWM controller. I just have to make sure I dont load up the motor past its 180v. Ill ask the guy about that later.
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Post by 92220 on Apr 20, 2024 10:23:15 GMT
Get an AC motor not use the DC motor at 180V.....180V is lethal when you get a shock !!!
Bob
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SteveW
Elder Statesman
Posts: 1,398
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Post by SteveW on Apr 21, 2024 12:20:36 GMT
So my choice was all wrong, I need a 10,000W SCR motor controller, a Bridge rectifier to change AC to DC and a vented metal box to put all the bits inside and earth. If I buy the most expensive SCR and Bridge its still cheaper than that first PWM controller. I just have to make sure I dont load up the motor past its 180v. Ill ask the guy about that later. Years back I did a project using small but powerful DC motors, supported first by a bit of research. Turns out electric motor aren't limited to much by voltage across them but the current through them. Basically, too much current cooks the winding and its game over. Getting them going round too fast should also be avoided. Focusing on our own electric locomotives we see a lot using the old stalwart Smiths 12 volt heater motor running from a pair of big 12 volt batteries wired in series. The key is a switching or pulse width controller that manages and limits the on duty cycle to control the motor speed. In essence if the 24 volts is only on for half the time the motor reacts as if its getting 12 volts. If you can control the on duty cycle of your power source to limit the current to a safe level of current through your 180 volt rated motor it should be fine. Also, be very careful with high voltage DC sources, anything much greater than 50 volts. DC doesn't spit you out to try again as AC can if you are lucky. By all means use DC but ensure your system is wired on the cautious side and includes interlocks to ensure safe access when servicing it. |
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Post by borderer on Apr 23, 2024 5:27:38 GMT
You say that your bandsaw presently has a 120 watt motor? Is this correct?
The treadmill motor is 2 HP. In round figures,1500 watts.
Replacing a 120 watt motor with one that has more than 10 times the potential power sounds like a recipe for disaster.
These machines are not toys.
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abby
Statesman
Posts: 927
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Post by abby on May 1, 2024 18:49:04 GMT
Why did you not remove the electrics from the treadmill ? I have done a similar transplant for my BCA jig borer . I removed all the electrics and fitted them into a suitable metal box , I can now control the speed from zero upwards with loads of torque.
Dan.
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