24VDC Reversing Motor located 2700FT away from power source
24VDC Reversing Motor located 2700FT away from power source
(OP)
I have a 24VDC reversing motor being moved 2700 feet from the controller power source. The motor requires 6 amps for normal operation but it is a torque motor in a valve actuator and requires 51 amps locked-rotor. Since it starts under a load the starting current is about the same as locked rotor, around 50 amps. I looked at a DC voltage drop calculator for a total of 5400 ft of #4 cable, I would need to start with about 100VDC to allow for the drop. Does this sound right? Thank you for any help offered.





RE: 24VDC Reversing Motor located 2700FT away from power source
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: 24VDC Reversing Motor located 2700FT away from power source
Keith Cress
kcress - http://www.flaminsystems.com
RE: 24VDC Reversing Motor located 2700FT away from power source
RE: 24VDC Reversing Motor located 2700FT away from power source
RE: 24VDC Reversing Motor located 2700FT away from power source
Depending on the duty cycle I'd run phone cable.
Add a deep cycle battery at the motor. Charge the battery via one pair of phone wires and control the motor with another set. All DC so no long-line latch-up problems.
Use the charge lines as a dropping resistor. Feed the local end of the cable with the float voltage for the battery plus the calculated drop at its float current draw.
The battery will be a foot or two from the motor and can provide all the starting current the motor will ever need.
Keith Cress
kcress - http://www.flaminsystems.com
RE: 24VDC Reversing Motor located 2700FT away from power source
RE: 24VDC Reversing Motor located 2700FT away from power source
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: 24VDC Reversing Motor located 2700FT away from power source
Of course it all depends on the duty cycle. In any case, the wire size will always be waaaay smaller than if you directly tried to start the motor because you only need to send the average current down the lines. You might need to run CAT5 for eight wires. Of course you'd have to run all the numbers once the duty cycle is accurately known. You might even want to run 2 CAT5s as you could do other things or if the needed average current was greater you could pair them up.
BTW CAT5 is only $260 per 1000ft (8 wires)
Keith Cress
kcress - http://www.flaminsystems.com