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| Need Wiring Help For 12 Volt Motor |
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| vtsteam:
Okay, the explanation: Your relay should have 8 connection locations on it. 2 for the coil (from your picture, first post, it looks like they are the bottom 2 larger lugs) 6 for the DPDT switch that the coil operates. That DPDT switch is just like any other normal DPDT switch. It seems like you know how to wire a DPDT switch -- this is no different. As you probably know, a DPDT switch is basically two switches in the same case that are mechanically connected together, so they close at the same time. And those two switches have a center movable contact that closes with fixed contacts at ether end of the switch. So you have two connected positions for the switch. Using the DPDT switch analogy, a relay has a spring in it holding the switch closed to one side. When power is applied to the relay's coil it moves the switch to the other side. That is the whole operation of a relay. The center contacts on the relay's switch are called the "armature", and the switch's end contact is either referred to as "Normally Open" or "Normally Closed", depending on which end it is located at. When no current is flowing through the coil, our switch is held by the spring to one side, and the contact on that side is the "Normally Closed" contact. The contact on the other side is not connected to anything, and so is the "Normally Open" contact. That's all there is to that. Your relay should have the connection lugs labeled, and/or a small schematic diagram indicating which contacts are which. If you can include a picture of that it will be easier to draw you a wiring diagram, like the one you showed. Okay, so that's relays. Next, the joystick..... |
| vtsteam:
The joystick you have is a 4 way joystick with 4 SPST switches, one for each direction, and a center position where no switch is closed. I don't know whether all 4 switches are connected together on one contact of each switch (in other words they have a common connection) or whether they are completely independent, We want two of the switches opposite each other to be connected together on one of their contacts. So if the joystick is already common connected, fine. If not, you can do that manually with a short wire. That common point will also be connected to the + side of your power supply. Therefore, when you move the stick to either extreme, one or the other switched contacts will get + voltage on it. So much for the joystick. Next...... |
| vtsteam:
Now our relay coil can only be ON or OFF, but we have a joystick with 3 positions on it -- Left, center, and right. This means two positions of the joystick (center and one side) will have to do the same thing, as far as the relay goes. I'm choosing to de-energize the relay for 2 positions of the joystick, and energize it for one. So how do we get 3 different results with the mill table out of that? To solve this problem we are going to let one joystick switch make a dual connection, and the other switch make a single connection, while the center position will make no connection -- three different circuit results, which can yield three different movement options for the mill table. The first switch will pull in the relay, AND supply current to one relay contact. In this case a Normally Open (NO) one. Since the relay will be energized, this contact will be closed, and if it is connected to the motor, it will run. The second switch will NOT be connected to the relay coil, so cannot pull in the relay. Instead it will be connected to a Normally Closed (NC) contact and since the relay isn't energized, that contact will be closed, and will be able to pass current to the motor. In this case it will be connected to the opposite contact on the motor than the first switch was, and so it will run the motor backwards. The middle joystick position, will not connect the + side of the power line to anything. Not the relay coil, or any contacts. Therefore, the motor cannot run. The rest of the circuit is there to connect the minus power supply to the relay contacts, in such a way that it gets connected to the correct side of the motor to complete the circuit, depending on which joystick switch is active. |
| vtsteam:
Here is a picture of the first schematic (without labels to make it easier to see) and the same circuit with the PWM added -- this would be the second joystick, the one with the detents. Obviously they would share a power supply when you build it, but I've kept that apart to make it easier to read here. You would probably also add a fuse, pilot light, and on/off switch for the power supply -- but again, I left them out for clarity sake. (ignore the pin numbers on the PWM in the drawing -- they were auto-numbered and may not match your PWM speed controller) |
| snub:
vtsteam, I really appreciate all this but I'm still slightly stumped. On your schematic/diagram (post #39) it appears to me that the relay has 10 connections. My relays function exactly as you described in post #40. I have to go as there is smoke pouring out of my ears from overloaded brain. |
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