delay a reversing circuit question.

Thread Starter

Scotty8

Joined Jul 23, 2017
5
Hello, I have a Garden Railway, and have a Ski gondola unit that is motorized.
The unit travels about 10 feet on a 45 degree angle - one gondola reaches the top, one gondola reaches the bottom.
OEM from the manufacturer ( LGB ), has a small circuit board which allows you to adjust travel speed, and delay before resuming the travel.
Alas, after years of service, the unit hesitates, skips back and forth, and torments me at every available moment.

I found this attached schematic on line that I hope will allow me to make a new 12 to 18 volt automatic reversing unit.

Parts are readily available and inexpensive

But I was wondering if there was a way to insert a delay circuit - to allow the gondolas to remain stopped for a few seconds before travelling again ?

Any recommendations as to what device I should use, 555 or a delay relay etc.

And do I need 2 devices, one up and one for down?

And can you tell me if I insert the device at the motor or... ?

Thanks for any help - the squirrels are laffing at my lack of electronic knowledge.

homersaysdoh.jpg
lgbrigi.jpg
 

Thread Starter

Scotty8

Joined Jul 23, 2017
5
What is the size of the motors? What are those switches ? i assume Limit switches?
Max.
Hello, one 6 volt or 12 volt motor, have both, both will do the job.

And yes those are limit switches to activate the relay to change the gondola direction.

Thanks...
 

MaxHeadRoom

Joined Jul 18, 2013
24,209
By size I meant current rating.
As if implementing a different circuit the two L.S.'s could be in series with the motor with a diode across the switch.
Max.
 

AnalogKid

Joined Aug 1, 2013
9,623
Generally speaking, it takes two switch devices (relays, power transistors, etc.) to accomplish the three states (forward, backward, wait). This can be one DPDT reverser (2/3 of the relay in your diagram) plus a SPST interrupter for the delay, or two SPDT relays - energize one for up, energize the other for down, don't energize either for wait.

The erratic behavior probably is age/corrosion/crud in the switches and in the relay contacts. Do you want to try to resurrect the original system and then add the delay function, or scrap everything but the speed controller and start fresh? Either way, a power interrupter has to go between the reversing relay and the motor, so power is killed to the motor but the rest of the system (including the new delay circuit) still is live. A 555 or equivalent monostable circuit that is triggered by either direction change is pretty straightforward.

ak
 

Thread Starter

Scotty8

Joined Jul 23, 2017
5
Generally speaking, it takes two switch devices (relays, power transistors, etc.) to accomplish the three states (forward, backward, wait). This can be one DPDT reverser (2/3 of the relay in your diagram) plus a SPST interrupter for the delay, or two SPDT relays - energize one for up, energize the other for down, don't energize either for wait.

The erratic behavior probably is age/corrosion/crud in the switches and in the relay contacts. Do you want to try to resurrect the original system and then add the delay function, or scrap everything but the speed controller and start fresh? Either way, a power interrupter has to go between the reversing relay and the motor, so power is killed to the motor but the rest of the system (including the new delay circuit) still is live. A 555 or equivalent monostable circuit that is triggered by either direction change is pretty straightforward.

ak
Generally speaking, it takes two switch devices (relays, power transistors, etc.) to accomplish the three states (forward, backward, wait). This can be one DPDT reverser (2/3 of the relay in your diagram) plus a SPST interrupter for the delay, or two SPDT relays - energize one for up, energize the other for down, don't energize either for wait.

The erratic behavior probably is age/corrosion/crud in the switches and in the relay contacts. Do you want to try to resurrect the original system and then add the delay function, or scrap everything but the speed controller and start fresh? Either way, a power interrupter has to go between the reversing relay and the motor, so power is killed to the motor but the rest of the system (including the new delay circuit) still is live. A 555 or equivalent monostable circuit that is triggered by either direction change is pretty straightforward.

ak

Yes - scrap the old, build new - the diagram above is from a fella on the youtube who made a camera slider

So I downloaded his schematic, ordered the parts, and gonna put it together tomorrow.

So the old unit is yesterdays news - gona build new as per schematic.

Wasnt sure what to use for a delay, where to insert it in the circuit - and would I need one or two delat devices.

Thanks for your reply...
 

AnalogKid

Joined Aug 1, 2013
9,623
One delay circuit with one or two inputs, depending, and one output to a relay.

Are you keeping the old speed control, or does your system not have one?

Can you sketch a wiring diagram of *your* motor, switches, etc?

ak
 

larrydd

Joined Nov 4, 2015
3
You might want to check the part number of the existing relay, it may be a latching type. That's what I would use to keep the circuit as simple as possible. If so, a 556 (dual 555) would be the simplest way to go. Don't forget to put a reverse polarity diode across the coil(s) to avoid the inductive pulse when the relay coil discharges (voltage is removed).
 

Thread Starter

Scotty8

Joined Jul 23, 2017
5
You might want to check the part number of the existing relay, it may be a latching type. That's what I would use to keep the circuit as simple as possible. If so, a 556 (dual 555) would be the simplest way to go. Don't forget to put a reverse polarity diode across the coil(s) to avoid the inductive pulse when the relay coil discharges (voltage is removed).
Thanks, The fella that made the camera slider did have a diode across the PWM, see his attached diagram for dummies
 

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