My first project done for 2022

[one32 HRW Forum Veteran Find all posts View Profile Close one32]

I did a good work over on this Scalex t bird this weekend New gears, wheels, tires guide bushings paint and decals
I want to keep the car digital ready, and hope I didnt mess up. I cut the capacitor off at the motor, in order to get a better fitment. After I cut it
it dawned on me that that may be part of the digital works. Any one know? Info would be great, and
What is the capacitor designed to do ?
The "upgrades" made a big difference in performance. Car is faster, and quieter going around the track. Thanks for the video's Harry

[arroldn HRW Forum Veteran Find all posts View Profile Close arroldn]

The capacitor is used to suppress noise and sparks is my understanding. You might want to read this response.

The whole point of the capacitors is to suppress sparks at the commutator. Sparks create radio waves. (Really early experiments with radio used sparks to create their Morse-code signals.)

It is the sudden breaking of an electrical current that causes the sparks. That current has a momentum (inductance) whose energy has to go somewhere. Its best option is to jump across the gap that just broke the circuit -- a spark.

But a capacitor provides an alternate path. A capacitor will allow that frustrated energy to go directly to the ground wire. Spiky, noisy electrical energy will go through a capacitor easily. But steady DC power won't go through.

The immediate result of adding a capacitor across the motor leads should be a noticeable decrease in the sparking at the motor's commutator.

Kids! Try this at home!

Ed Bianchi

PS - Another benefit of reducing the sparks is that the commutator brushes will last longer -- less 'spark erosion'.

[one32]

Thank you very much

[Brad_T HRW Forum Veteran Find all posts View Profile Close Brad_T]

Your car looks great Eric, the capacitor is as Ed explains above. The changes you made will definitely make a huge performance improvement but need to ask; did you leave the stock axle bushings?

[one32 HRW Forum Veteran Find all posts View Profile Close one32]

Thanks Brad
No I did not use the stock bushings, I used the Sloting plus SP053003 bushings from SCC with the self centering bushings (SLOT IT ) type inside the bushing.
They are the victor lll type. A little pricey, but I like them a lot

[Brad_T]

Thanks for the clarification, they looked like the stock plastic bushings in the picture. I have used the same bushings but must have been an earlier version as mine are a different color.

[arroldn HRW Forum Veteran Find all posts View Profile Close arroldn]

Put that Bird in the ForumsCup Proxy it looks like a good entry to me. Only needs a motor swap. Nice paint job and livery.

[one32 HRW Forum Veteran Find all posts View Profile Close one32]

Thank you sir

[Barc 1 HRW Forum Veteran Find all posts View Profile Close Barc 1]

Removing the capacitor's of course will do the opposite of what they were put on for. If you find your timing systems starts going wonky, it could be because of the electrical interference caused by your unsuppressed motor

[williamg HRW Forum Veteran Find all posts View Profile Close williamg]

nice work, looks great

[RichD HRW Forum Veteran Find all posts View Profile Close RichD]

The black ceramic thing that the legs of the capacitor go through is ferrite, the two parts together are sometimes referred to as the "ferrite man". The ferrite acts as an inductor and is half of the RFI filter. If you want to use the car in a digital system you will need to replace the ferrite man. Without the RFI filter you might have problems with a computer based timing system.

[one32 HRW Forum Veteran Find all posts View Profile Close one32]

Thanks for the info and likes guys. I really appreciate it.

[HomeRacingWorld Skunkworks Janitor Find all posts View Profile Close HomeRacingWorld]

Just an outstanding job.

I remove them (the RFI) all the time. No issues with our Trackmate systems. Digital I have no idea.

[one32 HRW Forum Veteran Find all posts View Profile Close one32]

Thanks boss
I will try it digital. If everything goes crazy, at least I know where to start.
I have thought about leaving the cap in line, and extend the leads to the motor. Only one way to find out