current limits
12 years 11 months ago #29525244
by burgerman
current limits was created by burgerman
I was reading on another (your?) forum that the controller has issues with big motors that can take large currents when stalled. Now I am used to playing with wheelchair 120 amp controllers and big 4 pole motors. These can be stalled without issue.
I am waiting impatiantly for my 150 amp per channel roboteq controller to arrive. If I try to climb a ramp and the motor stalls and takes a lot of current I expected the roboteq to simply limit this to 120, 140 or whatever I choose. Is this the case or will I have smoke from the controller? Why would it need a <250 amp peak ? (I suspect that my motors may peak a bit higher stalled)
Is this the time it takes to gain control and throttle back?
I dont want to damage the controller! This stalled condition happens pretty frequently with the average powerchair. I want a safe setup that is reliable.. Any advadvice?
I am waiting impatiantly for my 150 amp per channel roboteq controller to arrive. If I try to climb a ramp and the motor stalls and takes a lot of current I expected the roboteq to simply limit this to 120, 140 or whatever I choose. Is this the case or will I have smoke from the controller? Why would it need a <250 amp peak ? (I suspect that my motors may peak a bit higher stalled)
Is this the time it takes to gain control and throttle back?
I dont want to damage the controller! This stalled condition happens pretty frequently with the average powerchair. I want a safe setup that is reliable.. Any advadvice?
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- roboteq
12 years 11 months ago #29525259
by roboteq
Replied by roboteq on topic Re:current limits
The controller will throttle back so that it delivers the max current allowed by the current limit. Normally, your wires and motor will burn before the controller. You need to watch for this.
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12 years 6 months ago #29525453
by burgerman
Replied by burgerman on topic Re:current limits
The 150 amp limit? Or some really low figure? After reading another similar post here I am very worried!
Here dev.roboteq.com/dev1/online-forum/genera...hdc2450-power-output
Here dev.roboteq.com/dev1/online-forum/genera...hdc2450-power-output
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- roboteq
12 years 6 months ago #29525463
by roboteq
Replied by roboteq on topic Re:current limits
It is a real value but it is the current that is measured at the motor, not the current issued by the battery. The two may be different. See discussion in the manual.
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12 years 6 months ago #29525467
by burgerman
Replied by burgerman on topic Re:current limits
I totally understand that a 150 amps at the motor could be 50 or less at the battery cable. Its simple physics.
What worries me is that it will see like 150 plus at the motor at say 10 percent duty cycle and cut back to a lower figure. Like 40 or 70 amps...
That wont give me the torque needed. Mobility controllers will not let you exceed their max rating, but do not cut back to less than that, unless you program them to do so in numerous ways... So a 100 amp unit will give 100 amps even into a 40mohm motor.
What worries me is that it will see like 150 plus at the motor at say 10 percent duty cycle and cut back to a lower figure. Like 40 or 70 amps...
That wont give me the torque needed. Mobility controllers will not let you exceed their max rating, but do not cut back to less than that, unless you program them to do so in numerous ways... So a 100 amp unit will give 100 amps even into a 40mohm motor.
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