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Science lesson needed...


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#1 JewelryMonk

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Posted 20 February 2018 - 12:01 PM

Ok gang.

I am a couple months into this T-Jet addiction and I can see it not going away anytime soon.

I need a better understanding to get my stable of "6" cars going a little faster. (6 cars this week anyway) (Supers and Stocks)

Questions:

1. What is the relationship between the magnets and the armature?

   a. What works better together, strong magnets with a low ohm arm, weak magnets with a high ohm arm, match magnets with any arm????

   b. What spacing am I looking for between the magnets and the armature?

   c. How do I get a good measurement of the gap?

   d. Am I just looking for balance of weight and equal resistance between the poles, or a higher or lower number?

I understand there are a lot of "secret sauces" out there and many people don't want to divulge their recipe, but tips and pointers in the right direction would be really appreciated.

I will work on understanding gear mesh, weight, balance, handling, tires, shoe travel, ........etc later, I just want to know the power end of it first, so I know what I am searching for.

......AND speaking of "Searching For", if any of you guys (gals) have a pile of parts that you could part with, so I can do some testing, I would probably be in the market. I will be scouring Ebay as well.

 

Thanks so much in advance

Doug


Doug Napier
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Promoting Dirt Racing in the Black Hills area
 




#2 Walt G. Pierce

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Posted 20 February 2018 - 01:33 PM

If you are from the Black Hills area of South Dakota, you may want to get in touch with the HOSERS slot car group (link below). They have some great drivers and car builders. I am sure they can help you with some tuning tips.

 

https://www.facebook.com/RCHOSERS/


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#3 Ramcatlarry

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Posted 21 February 2018 - 01:27 AM

1) If you take one out (magnet or armature), the motor does not work.  Basic hi school physics of a DC electric motor: One North and one South magnetic magnet will spin an odd number of armature poles with each pole wound in the same direction.

1a) Weak magnets and/or higher ohm armatures are slower in torque and RPM than the opposite.

1b) Smaller air gap will have the effect of stronger magnets.  They should never touch each other and allowance for bushing wear must be taken into account.

1c) feeler gauge or separate caliper measurements.

1d) Both balance of weight and equal resistance in the poles is a goal within every wind. Lower resistance indicates less resistance in the fabrication such as no cold solder joints.  A super-low resistance on one pole would indicate a mechanical short.

 

Noise is friction other than the air friction of the spinning armature.


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Larry D. Kelley, MA
retired raceway owner... (for now)
race directing around Chicago-land

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60+ year pin Racing rail/slot cars in America


#4 Randy Tragni

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Posted 21 February 2018 - 04:26 PM

What Ramcatlarry said above is correct but also consider current (amperage). Stock motors were set up to work with small transformers. If you add stronger magnets and/or a lower resistance armature you will likely need more power to drive it.

You better also consider rules too if you plan to race against others. Many organizations have boundaries on what you can change/modify within the chassis. With t-jets plan on hand selecting the best components from a large number of chassis as you are severally limited in what you can change. Components from DASH are usually allowed and have better performance than most stock t-jet stuff. Not all organizations allow for their use though.


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