Using a variable voltage power supply

[slothead]

I just bought a variable voltage power supply and want to hook it up so I can still use the Scalextric power bases mounted under my wood tracks. Wires connect the power base rails to the copper tape above for each lane. I do this because I have Professor Motor controllers with Scalextric plugs on the end I don't want to cut off.

Scalextric wall warts are AC, but now I have a DC power supply and want to know if this will still work with the power base? The power base must use a rectifier to convert AC to DC so perhaps the DC current will just flow through one side of the rectifier and work just fine.

Anyone try this?

Slothead

[eeprof]

Slothead,
In theory that would work, however as I remember the diodes in the Scaly power track are only 1 amp diodes, so you could fry them depending on what cars you run on the track.
Greg

[HomeRacingWorld]

I tested this years ago and never harmed the power base. But I didn't push hot motors either.

[docdoom]

I think that the wall warts 15 volt dc out 120ac in 15 volts out at 2amps

[arroldn]

Slothead,
After burning up 2 power bases I contacted the guys at SlotCarCorner. They sell a track wired that allows you to use the power base for your controllers and power from your power supply. Run the power straight into the power base and follow the instructions. I have been running this for 3 years now with no problems with the power base.

[Mitch58]

I have 30' of Strombecker track the I had hard wired for brakes and was connected to an AFX wall pack through an RC type plug connection. When I got my Variable power supply I just cut and stripped the wire going to the AFX unit and hooked them up to the new supply. It has been about a year with no issues. I don't know anything about Scalextric power supplies though.

[SlotCarCorner]

[slothead]

I must admit it never occurred to me to put a fuse or circuit breaker on either track, I guess because even though I have routed tracks the power setup is just like a plastic track, none of which are fused.

If SCC will make a power base type module that accepts Scalextric controller and power supply plugs that would be ideal, then all I'd have to do is connect the 2 output wires for each lane. If it had a resetable circuit breaker in case of a short that would be all the better.

SCC - send me a PM if I can place an order.

Slothead

[SlotCarCorner]

[SpeedyNH]

substitution-wise, you can hose a nice DC supply into a former wall wart AC input any day; it will just automatically go to the right place through the internal diode rectifier bridge, albeit with a couple of 0.6V or so series diode drops internally. so you may notice that the Track Voltage is somewhat lower than what you actually put in, because of that drop through the internal AC rectifiers.
or you could always just open it up and bypass them! and as said above, don't have more current available than the rest of the circuitry can stand. most decent adjustable DC power supplies nowadays have a max current adjustment, so you could always limit it, and tape the knob down.
speedy

[RichD]

If your aftermarket power supply has an amperage adjustment do not use it, always leave that control turned all the way up. Slot cars pull a lot more current than you would expect when they first start up, I have measured 2 amps with Slot.it 21.5K motors. With a four lane track that would be a total of 8 amps with all of the cars starting up at once, like you would get at the start of a heat. If you turn down the amperage control the power will drop a lot and the cars will slow to a crawl, that could also happen if all of the cars were just accelerating at the same time. With a big power supply you must have fuses or breakers for each lane. If there is a short circuit a controller, power supply, track wiring or a car's motor could burn up immediatly. I was at a race where the track rails got hot enough to melt plastic.

[SpeedyNH]

well, what I meant was, if you're replacing a low-current wall wart in an existing toy car circuit, watch out for wiping out the internals.

[Mitch58]

Good point about the fuse. One of those things I kept putting off. I added one today. It probably took all of 15 minutes.