Seep point motors

[russ p]

I'm going to rewire the few that I've done in 0.75 cable

[TheSignalEngineer]

That's a lot of capacitor, 4x 4700microfarad capacitors are going to take a bit of charging. A bit of overkill? Having said that, once fully charged it should throw quite a lot of ends a once.

 

The Gaugemaster and Peco units have 4400microfarads, so less than a quarter of the capacitance of that one. Charging time is directly proportional to the capacitance so is bigger really better?

[TheSignalEngineer]

I'm going to rewire the few that I've done in 0.75 cable

I made up mine with a flying lead to a chocolate block then used the 16/0,2 from there to the panel. On the first lot I did the flying lead was only 7/0.2 but being about 9" long it isn't a problem. The reason I used a separate common return conductor was to save on cores in the feed cable. It's a bit bigger than needed, probably enough to carry the current of 20 operating at once.

[russ p]

I should have asked on here about which CDU to buy, for some reason forgot to do it

Will the 4.5A supply I've got charge it?

[TheSignalEngineer]

It should do, the output from a controller auxilliary supply is usually 1 amp. The recommended maximum charging voltage is usually 16 volt AC or 24 volt DC.

 

The way the circuit is wired on the board, using the output via a point motor should effectively switch off the input circuit, so you don't short out the power supply. As point motors are controlled by a probe, push button, passing contact or centre off non locking switch they will only have a momentary pulse.

 

Once the output is disconnected the capacitors should start to charge. Because the stored charge rises on a curve it will reach 63% of the charging voltage quite quickly depending on the resistance of the charging circuit. This is the Time Constant for the particular circuit. As the rate of increase drops away it takes 5 times the time constant to reach 99% of the charging voltage. 

[russ p]

How long will it actually take to charge and how quick will it be completely discharged?

[TheSignalEngineer]

It depends on the circuit resistance.

 

For example the time constant is circuit resistance in ohms x capacitance in farads. The Steady State time is 5x the time constant

[russ p]

It depends on the circuit resistance.

 

For example the time constant is circuit resistance in ohms x capacitance in farads. The Steady State time is 5x the time constant

A bit lost with that , a rough time would be ?

[TheSignalEngineer]

A bit lost with that , a rough time would be ?

I'm not sure of the exact values but I've had a meter on the circuit and I would estimate that the Gaugemaster set-up using a nominal 16 volt AC reaches the steady state at about 23 volts DC in 1 second from releasing the push button when the points have thrown. At that voltage Seeps go over like a Westinghouse EP machine.

[Chris M]

That's a lot of capacitor, 4x 4700microfarad capacitors are going to take a bit of charging. A bit of overkill? Having said that, once fully charged it should throw quite a lot of ends a once.

 

The Gaugemaster and Peco units have 4400microfarads, so less than a quarter of the capacitance of that one. Charging time is directly proportional to the capacitance so is bigger really better?

Yes! Well it all depends how many points you want to throw at the same time. I have one that size and can throw 5 peco point motors at a time. Charging only takes about a second but you can hear the transformer doing it.

4700 microfarad should be sufficient for one point motor at a time.

I have used both Peco and Seep and not encountered a problem with them having enough power to flick points across. They do have to be well aligned and centralised.

[kevinlms]

Yes! Well it all depends how many points you want to throw at the same time. I have one that size and can throw 5 peco point motors at a time. Charging only takes about a second but you can hear the transformer doing it.

4700 microfarad should be sufficient for one point motor at a time.

I have used both Peco and Seep and not encountered a problem with them having enough power to flick points across. They do have to be well aligned and centralised.

The last point (sorry!) is very important. Any point motor needs to be properly aligned in both planes.

[russ p]

Before I fit motors I put balsa wood in against each blade to keep the tie bar central then fit motor with rod in mid position

[TheSignalEngineer]

Before I fit motors I put balsa wood in against each blade to keep the tie bar central then fit motor with rod in mid position

That's right, I used a couple of scrap bits of Evergreen strip as scotches.

[DaveF]

I've just spent this afternoon fitting 2 Seep solenoids in very inaccessible locations - having managed to "need" to lay 2 n gauge points above some baseboard framing.  You would think I'd know better having been building layouts for well over 45 years.

 

As a result I couldn't put them underneath with the drive pin in the hole in the tie bar end.

 

I ended up drilling a large hole in the baseboard 1.5" from the end of the tie bar and centred the Seep below it - with blutack to hold it in place and I also tacked them in place with EvoStik .

 

As they were both in locations where I couldn't even see the screwholes in the base I then had to put the screws in by feel.

 

The operating pin is attached to the point tie bar with a piece of steel wire, they worked first time.

 

Lastly, I always test my point motors after installation on 16V AC, without a CDU.  If they work like that then I can be more certain they will always work well once the CDU is connected.

 

David

Edited March 5, 2018 by DaveF

[russ p]

I've ordered some better cable so I'm hoping that performance will improve with the new cable

I've spent quite a bitbof time this afternoon soldering fly leads onto about fifteen motors

Still got another 25 to do .....