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Power problems

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  • Power problems

    I have a power question. I have an aftermarket adjustable power supply 30 V - 10 Amp. LONGWEI INSTRUMENTS (on Amazon)
    I have set the output voltage on the power supply at 19.75 V to I get 18V at the track rail.

    I have a 49 ft track with 2 lane changers and no power taps at the moment. I was running 3 1/24 scale cars and after about 5-6 minutes the cars start to bog down and I get a beeping sound from the power unit and the cars start slowing down and eventually stop. They start up again a few seconds later. The power supply is drawing about 1.5 amps with 3 cars running and about 1.75 amps with 4 cars. I never had this issue with my last set which was bigger than this set and running as many as 7 cars with no issue.

    Here is another clue..I just tried it again and when the cars start slowing down the current flow light comes on and the cars stop. Under normal running conditions the current light is out. It sounds like a transformer over load.

    Thanks for your help.
    Last edited by spikes 914; 12-21-2020, 12:35 PM.

  • #2
    What amperage is your PSU set at?
    You say beeping from Power unit, are you referring to the control unit or your adjustable PSU?


    • #3
      Sorry I was not clear. The beeping comes the Carrera Control unit. The power supply is set 19.75 V which is 18V at the track rail. If I set it at 18V at the power supply its only about 16.8 at the track. I am using my multimeter to check it.
      Last edited by spikes 914; 12-21-2020, 01:19 PM.


      • #4
        So I tried it again this time with only 2 1/24 scale cars. It was drawing about on 1.2 amps. It failed in about 2 minutes. This was originally a 1/32 scale set, so I put my stock 1/32 transformer back in ran 3 1/24 scale cars for 8 minutes no issue.
        Maybe I should get a stock 1/24 Carrera transformer


        • #5
          Spikes, what Carlos was referring to was the AMP setting on your Power Supply, not the voltage. The CU can handle up to 8a. I'm pretty sure that your Longwei PS has adjustable amps as well as adjustable voltage. I'm not real knowledgeable on what may be wrong so I'll let Carlos or someone else answer.
          That PS is perfect for your track. I wouldn't go back to a stock PS, but maybe there may have been a malfunction in yours or the CU
          Sorry I can't really help with the actual problem, But I'm sure Carlos will get back with you soon.


          • #6
            You could well be on to something. If the PS has adjustable amps and the max is turned down too low, that could cause the issue being described.


            • #7
              I bought a LONGWEI 30V 10A Model - I have it set for constant voltage as opposed to constant amperage - I had it set at 18v and the amperage would be reading about 1.5 amps.
              I thought if you choose constant voltage the PS would automatically adjust the amperage needed.


              • #8
                Not exactly. I'll try to find the manual online. Some PSU's allow you to adjust the voltage AND the amperage independently while some allow you to adjust one or the other. But the problem you're describing sounds like a simple case of voltage drop. This can easily be caused by setting the amperage too low. Good thing is that it's super easy to fix, provided you make the proper adjustments.

                See if you can set the amperage to 6 amps and see what happens. Dig out the manual and make the adjustment then let us know if that changed anything.

                I had a chance to search for the model you mentioned and found this one, here's a video with a review on it:

                If that is indeed the one you got then you have to turn the current up to about the halfway point and guess at what current it is set at.

                Short rant, feel free to dismiss: I personally really dislike these types of power supplies because you're guessing at the amperage setting. You have to turn it halfway and guess or turn it all the way up and install an inline fuse on the positive connection. Maybe years ago that was acceptable but there are PSU's with much better functionality for not a lot more money. Here's the one I would suggest for pretty much all slot car guys:

                With hat one y9ou set voltage and amperage independently. You have extremely granular setting down to the 2 decimal places(1/100th) with voltage and 3 (1/1000th) with amperage. But the best part of it is that you set it, then you enable it. What that means is that you can preset it before you attach anything to it. And it has memory so that you can have settings for 1/32 cars and 1/24 cars and for testing or breaking in motors, or even truing tires. The memory stuff isn't necessary but it sure is helpful.

                The main thing is that you need to have the ability to set your power parameters before you get going. And it's nice to monitor voltage and amperage in real time by watching the display. You can monitor your power with the PSU you currently have, but setting in perfectly is tricky because you don't have a readout of the actual amperage unless you attach a load to it while setting it.

                But my guess is you accidentally turned the amperage knob down too low.
                Last edited by carlosinseattle; 12-21-2020, 06:57 PM.


                • #9
                  Teach me something... Carrera Digital sets run at 18v? unlike Analog sets that run at 12v?
                  Isn't he burning out the system and cars by setting the Voltage too high?


                  • #10
                    Carrera D132 OEM power supply is 14.8vdc, D124 is 18vdc. There is about 1.5v less to the track for each. Everything seems happy to have the input bumped up to give OEM voltage at the track. The 124's really like a solid 18v to the cars.


                    • #11
                      Spikes I had the same problem with my ps in the beginning,here’s what I found,my power supply came with two sets of wiring with banana plugs one with probes one with clips. To set your amperage I take the two clips clip them together creating a short or grounded circuit. That allows me to turn amperage up or down you’ll see your amperage numbers as you adjust knobs I set mine to 5 amps and I have a. 5 amp inline fuse from power supply to carrera control unit. Once amperage is set pull your test probs out and set voltage to18-20. Since I’ve done this I’ve had up to 8 1/32 cars running at the same time and no power loss problems never seen my amps go over 2.2. There’s videos on you tube that explain it far better then my attempt here but it works.


                      • #12
                        Originally posted by Rokon View Post
                        Carrera D132 OEM power supply is 14.8vdc, D124 is 18vdc. There is about 1.5v less to the track for each. Everything seems happy to have the input bumped up to give OEM voltage at the track. The 124's really like a solid 18v to the cars.
                        Thank you for the clarification. I guess this is one of the reasons I'll never run digital. How would I run a Carrera 1/24 and a BRM at the same time?


                        • #13
                          Originally posted by dinglebery View Post

                          Thank you for the clarification. I guess this is one of the reasons I'll never run digital. How would I run a Carrera 1/24 and a BRM at the same time?
                          You'd change the max speed of the BRM. Each car can be individually set. So it is, in fact, far easier to do this than it is do do it in a competitive manner on an analog track.

                          It's OK to not like digital- everyone can run what they like. No need to invent reasons out of a lack of knowledge.


                          • #14
                            Bruce is exactly right. I have several motors in my cars that are so powerful they are run at 25% less power to be on par with the other cars.


                            • #15
                              Double Ditto to what Bruce and Dave said. It's interesting how someone would change out tires or a motor but then turnaround and say they're stuck because they might have to push a short series of buttons.