Forward and reverse motor control circuit

The careful observer will notice that the time-interlocking functions of TD 1В and TD 2В render the M 1В and M 2В interlocking contacts redundant. In like manner, TD 2В will prevent the вЂњForwardвЂќ pushbutton from energizing M 1В until the prescribed time delay after M 2В (and TD 2) have been de-energized.

When TD 1В times out, the contact will close and the circuit will allow M 2В to be energized if the reverse pushbutton is pressed. When the stop button is pressed, contact TD 1В waits for the specified amount of time before returning to its normally-closed state, thus holding the reverse pushbutton circuit open for the duration so M 2В canвЂ™t be energized. This being the case, the normally-closed, timed-closed contact of TD 1В between wires 8 and 5 will have immediately opened the moment TD 1В was energized. If the motor has been running in the forward direction, both M 1В and TD 1В will have been energized. What we want each time-delay contact to do is to open the starting-switch leg of the opposite rotation circuit for several seconds, while the fan coasts to a halt. If we use contacts that delay returning to their normal state, these relays will provide us a вЂњmemoryвЂќ of which direction the motor was last powered to turn. LetвЂ™s begin by adding a couple of time-delay relay coils, one in parallel with each motor contactor coil. What we might like to have is some kind of aВ time-delayВ function in this motor control system to prevent such a premature startup from happening. If the fan was still coasting forward and the вЂњReverseвЂќ pushbutton was pressed, the motor would struggle to overcome that inertia of the large fan as it tried to begin turning in reverse, drawing excessive current and potentially reducing the life of the motor, drive mechanisms, and fan. This could be problematic if an operator were to try to reverse the motor direction without waiting for the fan to stop turning. If our hypothetical motor turned a mechanical load with a lot of momentum, such as a large air fan, the motor might continue to coast for a substantial amount of time after the stop button had been pressed. LetвЂ™s consider another practical aspect of our motor control scheme before we quit adding to it. The вЂњStopвЂќ switch, having normally-closed contacts, will conduct power to either forward or reverse circuits when released. So here it is.Now, if either forward or reverse circuits are latched, they may be вЂњunlatchedвЂќ by momentarily pressing the вЂњStopвЂќ pushbutton, which will open either forward or reverse circuit, de-energizing the energized contactor, and returning the seal-in contact to its normal (open) state. But since I added the DPDT and SPDT option I thought why not. So I don't use it.I also don't use it because It has very limited parts as in no triple pole double throw relays. Circuitlab wants me to pay to use and save. This can also be done with a DPDT and a SPDT relay.ДЄdding this per. (Normally Closed) of the second LS to the N.O. Connect Negative Power to both the COMs of the LSs.The negative of the coil also goes to the COM (Common) of the 3PDT's third pole.(Normally Open) of first LS (Limit Switch). The negative of the coil goes to the N.O.Connect Positive Power to the relay coil.Wire the first two poles as if it were a DPDT reversing relay.Using a 3PDT (Triple Pole Double Throw) relay, The circuit is actually very simple but hard to explain. I know this post is 6 year old but, I hope this helps you in some way or at very least helps others who see it and need it? 1/2 a CD4011B) and a MOSFET H-bridge to drive the motor: Interrupt only the current to M1 and the memory of the previous direction will be maintained as long as V1 is applied (which means continuous draw if the relay is energized).ДЄ solid-state solution could use a single CMOS gate package (eg. Interrupt V1 to switch everything off (and it will always drive to the left when power is applied). The relay drops out, releasing the hold contact and it remains dropped out, and we're back where we started. The motor operates until SW3 is actuated, which interrupts current to the relay (D3 catches the flyback voltage). The motor immediately reverses, but the top contact has pulled in, keeping the relay energized through D2. When the motor reaches the left limit, SW2 is actuated, energizing the relay. The top terminal is positive, SW2 and SW3 are in the positions shown. The motor M1 drives to the 'left' when the top terminal is positive and to the right when the top terminal is negative. Here a DPDT relay and two microswitches are used. Simulate this circuit вЂ“ Schematic created using CircuitLab You will need a memory element such as a relay to hold the current direction of the motor.

Forward and reverse motor control circuit