Hi, I'm currently working on a project for controlling ball valves. Motors used for this operation are geared down 24V 775 motors. I'll be sensing limit positions with micro switches, but this will come to play in later text. The problem I'm trying to solve is the inrush current at start of the motors. Single motor draws around 500mA while running, but at the start, the current is around 1,5A (measured by an analog ammeter, about 1A by a digital multimeter). I intend to run two of these simultaneously, which would mean buying at least 3A switched supply, ideally 4A. But those are getting quite big for my application, and I think it is wasteful and overkill. I would rather buy 1,25 - 1,5A switched supply and solve the inrush current by some kind of softstart. For driving the motors in both directions, I'm planning on using L298N, but I'm open to suggestions.
The problem is that I'm not sure how to implement softstart circuit and what kind to use for it to work with a combination with H-bridge. The next thing to consider is that I need the motor to stop immediately after the voltage is cut by the H-bridge because I need the motor to stop at the limit position after hitting the microswitch. But some softstarts I've seen slowly ramp down after cutting the voltage to motor. I've considered using thermistors for limiting inrush currents, but I'm not sure if they would be able to cool down / recover to work properly again between the cycles. And in case of a faulty signal resulting in a quick startup after the last one, they would probably be of limited use. The solution to this problem might be to use a quick fuse on the output of the power supply, and in case of limited thermistor functionality, the fuse would get blown. I'll be glad for any help, thanks.
The problem is that I'm not sure how to implement softstart circuit and what kind to use for it to work with a combination with H-bridge. The next thing to consider is that I need the motor to stop immediately after the voltage is cut by the H-bridge because I need the motor to stop at the limit position after hitting the microswitch. But some softstarts I've seen slowly ramp down after cutting the voltage to motor. I've considered using thermistors for limiting inrush currents, but I'm not sure if they would be able to cool down / recover to work properly again between the cycles. And in case of a faulty signal resulting in a quick startup after the last one, they would probably be of limited use. The solution to this problem might be to use a quick fuse on the output of the power supply, and in case of limited thermistor functionality, the fuse would get blown. I'll be glad for any help, thanks.