Wires heating up
 

We have a CIM motor connected to a power source to continue testing our launcher and the wires are heating up. There are no other wires attached to the actual motor wires and they are warm right away.

Any suggestions,

chiefwebmaster

Re: Wires heating up
 

You'll have to describe your power source in greater detail. However, from the description given, limited though it is, I would guess that you're putting an awful lot of current through that CIM. This does two things: First, it heats the wires, as you're noticing. Second, it's going to affect the CIM's performance (I want to say it'll go faster, but I don't know that for sure). CIM performance affected = launcher performance affected = more tweaking while at competition.

Re: Wires heating up
 

CIM motors are quite robust thermally. However, they do heat up internally when loaded mechanically. The rate of heating increases as the loading increases.

Look here for some details of how the motor's brush gear heats when loaded. Keep in mind that the thermal connection between the brushes and the motor leads is pretty direct; i.e., when the brushes get hot, the leads will also. Although the example load conditions covered in the link are worst case, the general trend is the same for all load conditions -- brush holders (and therefore leads) heat up much faster than the motor case.

Re: Wires heating up
 

Be sure you have 12g wires in all your motor circuits.

Make sure all your connections are good and solid. A poor connection, for instance a bad crimp, can cause the circuit to pull more current, causing the heating. Poor connections and small wires add to the resistance in the circuit.

Check the resistance between the power source and the motor leads, if you can get to them. Heating goes as current squared times resistance, so a little resistance can cause a lot of heating at the currents that the CiM pulls.

Dr. Bob
Chairman's Award is not about building the robot. Every team builds a robot.

Re: Wires heating up
 

First of all a CIM motor is a current or torque device. The more armature voltage you apply the speed and current increase proportionally. So if your load changes or you have a high load to begin with, the current will increase to keep the load speed. This speed is based on the speed reference. If your wires are heating up immediately you may be using the wrong gauge wire. What speed reference voltage are you applying? What motor are you using? What type shooter do you have? Is the motor coupled to a gearbox? How are you driving the motor? Are you using an encoder for speed feedback or are you using voltage feedback? Is your shooter a single motor type or are you running a two motor linear shooter? What speed are you running the motor/s at? These are some of the questions that have to be answered. Happy to help you out in anyway I can.