Thinking

[Andy4639]

What about a full drag cart with no controller. Pimp Daddy and I have talked about this before on another site but I have never seen anyone else speak of it.
Yes it would have to be pushed every where but... would it! Have the cart on the smallest controller you can and then once staged click the switches and take the controller totally out of the picture.
Dump full voltage and amps to the motor. This way you have no limit's on voltage, amps just add as many as the motor can stand. This would not be that hard to do I don't think!!!!
the only draw back is the staging area if you didn't use a controller @ all.
What do you guy's say or think about it?

 

[WALKNTALL]

I have actually though about that Andy. The mega volt dragsters have to hand stage. So I was thinking why the need for a controller. A giant contactor or 2, maybe for half pack then full pack and stack it full of batteries. Maybe an emergency shut off..

Why not?

 

[Andy4639]

My point as well. Just make sure you have some kind of emergency shut off in the line some place.

 

[Pimp Daddy]

Andy,
Thought more about this...Have two contactors one 1/2 the pack voltage to start with then the second with full pack with micro switches on accelerator to control whan they come in.

 

[Andy4639]

Yes I agree with that. I think the double contacts would be the way to go sorta like a boost if you will. I was basically just wanting thought's about the concept first then build on it. The only real problem would be that in the staging area @ the track. Some tracks don't allow anyone to help you stage. Then again as I suggest have some kind of controller that can be taken totally out of the system once staged.

 

[riverracer]

Thats what I am working on now Andy. Stock controller to start off and bypass straight to the motor.I am going to try it with a stock cc controller and how it works.

 

[Andy4639]

I figured that's what you were up to Riverracer. That's why I started this thread hoping to get more insight on the process.

 

[TDAWG]

Ya know the old Club Car systems with the 5 solenoids? I have always wanted to do this with one of those carts. The wiring is already in place, micros in the accel are already in place also. Just upgrade the solenoids with some HD ones and drop in a bunch of volts and hang on.

 

[Andy4639]

Good point TDAWG. How about someone that can do a drawing, schematic to wire one up for us. How many amps voltage will a motor handle sending it straight to it like this you wreckin?

I posted last night that a Rapture motor takes 72 amps, I have no idea what that means except maybe to get it moving...I don't know does anyone here know?

 

[StreetGlide]

Hello,

Most contactors are made to handle large amounts of current, but not to hot switch large amounts. "Mega contactors" would be definetly be required. Probably cost as much as a controller. I'm going to check.

Albrights sells one for EVs. (EV500) It will work with Zilla controller system and handle 600 to 1000 amps. It is nicknamed "Bubba" (no kidding). Only $1,448.00.

Have fun...

 

[Pimp Daddy]

Talking to JJ over there and he says it's possible and being done in some of the EV race cars.Have not read all the articles,but plan to.



http://www.poormansev.com/id43.html
http://www.aaroncake.net/Circuits/cntctcon.asp


My next question is the amp ratings on the motor, is the 72 amps FLA?

 

[Pimp Daddy]

Ran across this on the net...FLA amps are exceeded X12.


DC MOTOR OPERATION DC Motors DC MOTOR OPERATION DC motors require special starting resistors for operation due to their unique design. A knowledge of the operation of these starting resistors is necessary to understand DC motor operation. EO 1.11 EXPLAIN why starting resistors are necessary for large DC motors. EO 1.12 LIST the four nameplate ratings for a DC motor. Starting of DC Motors At the moment a DC motor is started the armature is stationary and there is no counter EMF being generated. The only component to limit starting current is the armature resistance, which, in most DC motors is a very low value (approximately one ohm or less), as shown in Equation (6-9). (6-9) Ia Et ECEMF Ra In order to reduce this very high starting current, an external resistance must be placed in series with the armature during the starting period. To show why this is essential, let us consider a 10-hp motor with an armature resistance of 0.4 ohms. If the motor were supplied by a 260 VDC source, the resulting current would be as shown in Equation (6-9). Ia Et ECEMF Ra Ia 260VDC 0 0.4W Ia 650 amps This large current is approximately twelve times greater than actual full-load current for this motor. This high current would, in all probability, cause severe damage to the brushes, commutator, or windings. Starting resistors are usually incorporated into the motor design to limit starting current to 125 to 200 percent of full load current.