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Amperage needed for VX arms?


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#1 David Mackey

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Posted 02 January 2017 - 09:51 AM

Anyone know what amperage VX arms need to run properly? My local track works fine with my VR 20 motors in 116-120 gram cars, running in high 7s @ 72 MPH but when trying to move up to VX motors it melts the braids and runs high 9s.

 

This is 1/4 mile strip and is a power supply. I think it's around 25 amps. I'm thinking they must need 100+ amps.

 

Thanks for your help.






#2 Ramcatlarry

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Posted 02 January 2017 - 12:26 PM

If  V-20 and VX you mean Velociraptor Neo magnet motors, then you are into the electrical power needs of the rest of the cobalt hign power slot world. 

When I rebuilt my King, I borrowed a fancy amp meter to test the amp draw of some wing cars. A Grp-27 (sort of a V-20) and the bigger wire opens would register over 40 amp draw each for the nano second of full power pull of the trigger. I ended up with two 8D batteries, a 90 amp power supply to charge them, some canister 2-3 Farad capacitors, and added a second #12 wire to the wiring harness to run the track.
 
There should be a common 'standard' for wiring drag strips to run high power cars. There isn't, and many tracks look good, but do not fulfill their potential that they could.

1) Big track braid. wide and thick. That is what Gerding uses on his best tracks built in the past several years.
2) Under the track is the wires. If you can afford it, use welding cable. Any track with less than #12 stranded wire is underwired.
3) Each lane must draw power from separate power sources. If not, the first car running gets more power - especially if the track has capacitors in the system. Nanoseconds count.
4) Batteries are cheap high amp power, but building inspectors object to the (unproven) hydrogen outgas explosive possibility in commercial buildings.
5) Power supplies have come a long way in the past 30 years. Never use a big battery charger on a slot car track for power. Better to use RV industry AC/DC convertors like IOTA/Bulldog type units. Even better is the use of high amp 'server power supplies' which need to be wired  in series since these are only five volts DC output so three in series can be tuned to get 16 volt DC output with over 300 amp output.


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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


#3 David Mackey

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Posted 05 January 2017 - 12:58 PM

Thanks! I replaced the arms with vr 20 arms and they run properly. I'm upset because I bought the motors at the track and they don't run as vx extreme should. And track does have common power source for both lanes.

#4 Ramcatlarry

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Posted 05 January 2017 - 01:37 PM

I believe that drag strips NEED the independent lane sourcing for power due to the load and short time power draws.  When the total race is less than one second, nanoseconds DO COUNT in who has a fair race.

 

I can see one reason to not have common power to a multilane track, and that is to have lane reversing switches as many homeset tracks  can.  Most commercial tracks only run in one direction and connecting the left braid to a common ground buss bar along with the red brake (fused) post is very common.  Each line to the white power line should be fused and is usually relay controlled to allow individual lane rental. Small or club track really only need to turn the entire track on or off with one relay and common power buss.

 

When you put the supercharger on your V-8 and NOT increase the fuel line diameter, you gain nothing other than a thinner wallet.


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

USRA 2017 member #404
USSCA  member

Host 2006 ISRA/USA
Great Lakes Slot Car Club member
60+ year pin Racing rail/slot cars in America






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