EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: okw on November 30, 2021, 01:13:51 pm
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Hi! My nephew (3y) is soon getting old enough to ride an electric 90s train we have. It has a simple momentary button on the handle, which engages the motor. This makes it jump forward, rather abrasively. I've been searching for a soft-start motor controller, but to no avail. All I can find is pot meter controllers for variable speed. I need on/off, but with soft start.
Anyone knows some Ali off-the-shelf products (DIY or prebuilt).
If not, I'm open to designing something (with the right input and help).
I do not know the motor rating as the motor is inside an plastic enclosure. But it doesn't look powerful (probably geared very low), and it's driven by a 6V 6Ah battery. It seems to have two motors, one for each rear wheel. I've attached some pictures, if that helps.
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Use a relay to start with the motors in series and then switch to parallel after a short delay.
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Simplest is a resistor in series with each motor, roughly rated to reduce the current to half the run current as measured with a meter. Then after a half second or so a relay closes, using a large value capacitor, that is part of a RC delay, to short out the resistor to run at full speed. Simple, works well enough, and reasonably easy to build. Otherwise a simple speed controller with DC input, and with a RC delay to allow speed to rap up as the time goes by with the switch closed.