The Tekin Current Limiter Function
Current limiter does just what it sounds like; limits the current going to the motor. However, how the esc actually does this and why you should use it sometimes isn’t so clear.
To understand how it works, we first need to understand what the point is. Limiting the current would be like setting the slipper looser. Allowing more current to flow to the motor is like tightening the slipper. More current = more torque in the same way a tight slipper will allow more torque through than a loose slipper. The key idea to take away from this is that neither one limits the top end of the car. A loose slipper will take a long time to top out on a drag strip, but it will get there eventually. The same goes for the Current Limiter. It limits acceleration potential, not top speed. However, it is much better (more efficient and less wear and tear on the drivetrain) to electronically limit the torque than to set the slipper loose. The slipper should be set just to absorb impacts from landing, not normal acceleration.
The current limiter can be set from 0 to 100 in Hotwire. 100 means the esc doesn’t think about the current going to the motor: whatever the motor wants it gets. Setting the current limiter to anything other than 100 reduces the maximum current allowed to the motor. The feel of this number is rather arbitrary, depending on your motor, gearing, vehicle weight, etc. People with like setups can trade current limiter values easily, but you will probably need to determine what current setting will be best for you on your own time. 80 is a typical number for mod motors that curbs harsh acceleration around 0 rpm or spikes caused from landing on power. 60 starts to really mellow out the torque output of a mod motor making for an easy to drive car in slick conditions. On the other hand, 60 might not even be noticeable with a stock motor. The best thing to do is go down 20 at a time until you notice a difference, then go up or down 10 for rough tuning, and finally 5 at a time to fine tune to a particular track.
HOW the esc does this is pretty straight forward. It measures the current passing through and if it approaches the artificial ceiling you’ve selected it will cut back on the throttle. Let’s say at 0 rpm your motor will draw 100 amps and at 10,000 rpm your motor now draws very little (0 for arguments sake). 100 amps at 0 rpm is full torque, but if we set the current limiter to 80 (and again assume with this motor it’s a straight forward 80%) while grabbing full throttle at 0 rpm, the esc backs off the throttle until only 80 amps are flowing through. As the motors demand for current drops off as it approaches 10,000 rpm, it’s safe to say that at about 2,000 rpm (20% of max) the motor can only draw 80 amps max. At this point the esc is back to providing full throttle having reduced the torque at takeoff allowing for a smooth start to your a-main.
Typical reasons for using the current limiter are preventing wheel spin on slick tracks, cooler running electronics by reducing power going through the system, smoothing out “nitro finger” for those coming from the piston packing side, or safeguarding against pulling to hard on the trigger when someone takes them out and the adrenaline starts flowing.
