$5 from the shop
works well as a hopper
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are you running this on 24v or 12v? how do they go on 12v? I ask as I have high current 12v PSU's but not 24v.
Thanks
Yep, 12v. 24volts would be way too fast. I got the idea to use this motor from reading that very website!Have a look on my website. I've got some info about the conversion. 12v is perfect as it give you 160rpm.
QldKev
Have a look on my website. I've got some info about the conversion. 12v is perfect as it give you 160rpm.
QldKev
Thank for the info. Looks like I was right in thinking that halving the voltage (24v - 12v) will halve the speed. I also think that the current would be doubled. That's not an issue for me as I have server PSU's that output 30+A B)
Looking at this to power my JSP Malt mill which has 10" rollers :super: The malt mill web site says it can run at up to 400rpm, but under 200 will be fine.
Beers
Crozdog
Talking DC, not AC as they are totally different.
At half the voltage your current draw is still the same, but you half the speed.
So usable power
250w / 24 = 10.4amp
10.4 * 12v = 125w usable; which happens to be enough torque for mm2 mills, and the correct RPM
If your mill is happy at 400rpm, does your power supply have a decent -12v capacity.
+12v and -12v = 24v
More torque and faster crush.
I would not run my mill that fast.
QldKev
i thought that 250W @ 12v = 20.8A i.e. same power with less voltage will need more current.
I have seen how guys have modded 2 PSU's I have to make 24v supplies.
I have several PSU's even 1 that can supply 147A @12v![]()
FYI, checkout this site for info on using many high current server supplies http://www.rcgroups.com/forums/showthread.php?t=1292514
If you wanted to have the same torque at a lower voltage you would need to reduce the resistance...
Ohms law states
I = E / R
I: current
E: voltage
R: resistance
so for a 250w motor at 24v we have E and I, we need to cal R
R = E / I
R = 24v / 250w
R = 0.096
so thus
I = E / R
I = 12v / 0.096
I = 125w
125w @ 12v = 10.4amp
resistance is a constant at any (I) voltage.
Yes I agree with ohms law, but I was thinking along the lines of power (P) = VI
I was assuming that if P stays the same & V halves, I must double. However i now realise that if V halves, I stays the same & P also halves.
What is the impact to torque? does it stay the same or halve? I think it halves...is that right?
Those motors are the cheaper versions of these motors:
http://www.motiondynamics.com.au/dc-motors...-rpm-clone.html
http://www.motiondynamics.com.au/dc-motors...or-400-rpm.html
Though I can get those if you guys want?
Yep, they certainly are!Those motors are the cheaper versions of these motors:
http://www.motiondynamics.com.au/dc-motors...-rpm-clone.html
http://www.motiondynamics.com.au/dc-motors...or-400-rpm.html
Though I can get those if you guys want?
Why use them when the 12v rail of an old pc power supply does the job?