Two Point Motors Alternating off Same Switch

[regme]

Hi

 

I have two point motors (Hornby) 1 and 2, running off the same switch (on-off-on) using a CDU to power them.

 

So the problem is, when I push the switch up Point 1 moves and Point 2 does nothing.  When I push the switch down Point 1 moves back and Point 2 does nothing.

 

When I push the switch up again Point 2 now moves and Point 1 does nothing, when I push the switch down Point 2 moves back and Point 1 does nothing.

 

When I push the switch up again Point 1 moves and the process repeats it's self.

 

From a previous post I have made sure all the wires are the same length, however I only have one feeder wire from the switch to a terminal block that then goes to the two point motors.

 

Any ideas?

 

Cheers

[Chris M]

I never have wires of anywhere near the same length on my layouts and one switch may have to throw up to 5 point motors at the same time. Some of these have wires direct to the points, some pass through diodes (which causes voltage drop) and some across a baseboard connector (which uses thin computer cable). There are three things I would check:-

1. Are they wired up correctly? I know this sounds obvious but if I have a problem with electrics the first thing I check is the circuit and the logic behind the circuit. It s amazing how often I have made a stupid mistake.

2. Are you providing sufficient input voltage to the cdu? They usually like 16 to 18 volts AC but always check the instructions because they aren't all the same.

3. Are the wires thick enough? It has been suggested many times that thin cable can have problems carrying the full thwack of a cdu. The wire doesn't have to be very thick, in fact some of mine is quite thin, but very thin wire may cause an issue.

4. Is your cdu man enough for the job? Some of them are pretty weak. I found the Gaugemaster one was not that great for my purposes. I now buy mine off Ebay. You probably need at least 10,000uF for reliable operation of two points. I use a 20,000uF cdu to switch five points at the same time.

 

In my experience item 4 is the most likely cause of the problem but it is worth checking items 1 to 3 before spending any money on a new cdu. Having said that you should be able to get a new one on Ebay for less than £10.

[regme]

Thanks for the reply so very useful information, especially since my electrical know-how is questionable, the gremlin has seemed to sort itself out.  It was only happening to one set of points, the others worked fine.

 

1. I have checked the wiring, all good

2. I'm supplying 16V AC, however I'm thinking of increasing it to 18V AC.  I was thinking of this, http://www.ebay.com.au/itm/18V-AC-AC-1300MA-POWER-SUPPLY-ADAPTER-18VAC-18-VOLT-1-3-AMP-1300-MA-APPLIANCE-/321561554795, but I'm not sure about what to do about the earth wire.

3. I'm running 24/0.2 wire to a terminal block then using the orginal wires that came with the point, maybe I should remove the orginal wires and replace them with the 24/0.2

4. My CDU has only a 4700uf capacity which I upgraded from a 2200uf but it could throw two points with the 2200uf capacitor. 

 

Thanks again

[DCB]

Thanks for the reply so very useful information, especially since my electrical know-how is questionable, the gremlin has seemed to sort itself out.  It was only happening to one set of points, the others worked fine.

 

1. I have checked the wiring, all good

2. I'm supplying 16V AC, however I'm thinking of increasing it to 18V AC.  I was thinking of this, http://www.ebay.com.au/itm/18V-AC-AC-1300MA-POWER-SUPPLY-ADAPTER-18VAC-18-VOLT-1-3-AMP-1300-MA-APPLIANCE-/321561554795, but I'm not sure about what to do about the earth wire.

3. I'm running 24/0.2 wire to a terminal block then using the orginal wires that came with the point, maybe I should remove the orginal wires and replace them with the 24/0.2

4. My CDU has only a 4700uf capacity which I upgraded from a 2200uf but it could throw two points with the 2200uf capacitor. 

 

Thanks again

I too have various lengths of wire, some through diodes, some through dodgy connector blocks but I use big thick wires, car wiring loop multi strand good for 10 amps and a very big Capicitor, like 40 against your 2.2 so big it needs spare point motors as dead loads so at least 4 points throw together so the rails dont rip out of the tie bars.

 

However for the past 15 years my 3 way point has behaved just like your crossover, only 1 set of blades moves first time and the other set when you try again.    Its Gremlins.  I humour them by leaving them alone, they know the 3 way point is the most inaccessible on the layout so they target it, It takes 2 hours to remove and replace the lower hidden sidings baseboard to get at it.  However I know it operates 2nd time so it's not a problem.  If I fixed it the Gremlins would have to find somewhere else to play, loosening layshafts on Q1's and chassis bottoms on 28XX for instance, or worse still migrate to the car.   Swearing loudly is a good albeit temporary way to remove gremlins.

[kevinlms]

Thanks for the reply so very useful information, especially since my electrical know-how is questionable, the gremlin has seemed to sort itself out.  It was only happening to one set of points, the others worked fine.

 

1. I have checked the wiring, all good

2. I'm supplying 16V AC, however I'm thinking of increasing it to 18V AC.  I was thinking of this, http://www.ebay.com.au/itm/18V-AC-AC-1300MA-POWER-SUPPLY-ADAPTER-18VAC-18-VOLT-1-3-AMP-1300-MA-APPLIANCE-/321561554795, but I'm not sure about what to do about the earth wire.

3. I'm running 24/0.2 wire to a terminal block then using the orginal wires that came with the point, maybe I should remove the orginal wires and replace them with the 24/0.2

4. My CDU has only a 4700uf capacity which I upgraded from a 2200uf but it could throw two points with the 2200uf capacitor. 

 

Thanks again

Increasing the input voltage will probably solve your problem. Don't worry about the earth wire, just cut it off.

 

The different length wires, won't make any significant difference, unless seriously long and too thin.

[kevinlms]

 some through dodgy connector blocks

Do you have a preferred supplier for these?

[Ron Solly]

A question - does each solenoid work  by itself each time you operate the switch? and I also assume the switch is a momentary non-locking switch?

Edited September 19, 2017 by Ron Solly

[Ron Solly]

I switch two solenoids at the same time ; nominal 15vAC and 4700UF works well even with accessory switches on the solenoids. I do make sure that there is nothing binding in the tiebar or solenoids.

[AndyID]

Hi

 

I have two point motors (Hornby) 1 and 2, running off the same switch (on-off-on) using a CDU to power them.

 

So the problem is, when I push the switch up Point 1 moves and Point 2 does nothing.  When I push the switch down Point 1 moves back and Point 2 does nothing.

 

When I push the switch up again Point 2 now moves and Point 1 does nothing, when I push the switch down Point 2 moves back and Point 1 does nothing.

 

When I push the switch up again Point 1 moves and the process repeats it's self.

 

From a previous post I have made sure all the wires are the same length, however I only have one feeder wire from the switch to a terminal block that then goes to the two point motors.

 

Any ideas?

 

Cheers

 

Do the two points form a crossover? If they do there could be a bit of mechanical interference between. That might explain the interesting "memory" effect you are seeing. Failing that you may have discovered a previously unknown electrical phenomenon.

[Brian]

For what its worth here's my rule(s) of thumb for solenoid point motors that's provided me with trouble free solenoid operation all my modelling life! 

 

1)  Use as the minimum 16/0.2mm wire for both feed wires and whenever necessary on return wires increase the wire size to 24/0.2mm or even 32/0.2mm or double up the 16/0.2mm of returns that are shared by two or more solenoids which move together.

2)  Don't link feed pairs from one motor to the next, ideally run separate feed wires to each motor from the operating lever or switch or stud.

3)  Ensure the motors move over and back freely by finger upon installation and then test each one on its own before wiring them together in pairs or triples.

4)  Use a 4700uF minimum CDU in the supply from the power source to first lever or switch or stud. (Not ideal with Hornby R044 Black levers though)

5)  Use a power supply that provides 16v AC or 19 to 22 v DC.

Edited September 21, 2017 by Brian