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Old 30-03-2017, 01:14 PM   #1
Flashbang
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Default Point Motors and their operation.

For powered point operation you need to make a choice...
Type of motor - Solenoid, Stall/slow motion or Servo and how they are to be operated - by Analogue or Digital means.

Solenoid motors are usually fairly cheap and plentiful to come by, available as direct point fitting or surface mounting or under baseboard fitting and have been used for many years to operate points electrically. How they are operated is your choice.
By DCC which involves adding a pulse output Accessory Decoder which provides a momentary pulse of power to move the motor over and the decoder interfaces between the DCC system and the motor(s). Some accessory decoders allow additional panel switches to be used to operate the points too.

Another option for the DCC user is to allow the trains to be DCC controlled but the points analogue controlled. (Equally for the DC user too). By feeding Analogue solenoid motors from typically a 16v AC or 19-21v DC supply and passing contact levers or sprung to centre off toggle switches or two non locking press to make push buttons or stud and probe is the individuals choice. Adding a CDU to Analogue fed solenoids will enhance their performance and prevent accidental coil burn out. Normally only one CDU is needed for the whole layouts analogue point operation.

Stall motors or slow motion motors are usually more expensive, but do give a nice slow and realistic point movement. They normally have two sets of change-over contacts built in. Such makes are to name two - Tortoise and Cobalt. Stall Motors can be Analogue or Digital. Analogue versions operate, depending on make, nominally from a 9 to 12 volt supply DC and draw little current to move over or when stalled at the end of their travel. Typically around 10 to 30 milliamp. They need a DPDT locking toggle switch and are fed usually from a regulated DC supply. LED indications can be wired into their operation pair of wires or use one of the sets of switch contacts built into the motor to feed the panel LEDs.
To operate these from DCC, the Analogue stall motors will need a separate Accessory decoder that provides a continuous output. Digital versions are also sold for some makes of stall motor. The Digital Cobalt ip is one such. This allows full DCC operation and the added option to have panel mounted push button(s) or a sprung to centre off toggle switch to manually operate the motor, but using the DCC power to move the motor over.

Servos are really the 'New Boys on the block' in railway modelling. They have been used for years by the radio control aircraft and boating fraternity. They operate from a special servo control board and are usually 5 volt DC powered. But you can obtain DCC Servo control circuit boards. Buying the servo itself is fairly cheap, but it normally has no means of fixing it to the baseboard, so a special servo mount bracket is also needed. They don't have any additional switching fitted, so one or two micro switches are also needed to be fitted and then worked by the servos movement. These provide switching for things such as frog polarity on electrofrog points, LED panel indications and signal aspect controls. For control panel operation you usually have a SPDT toggle switch to operate the servo via the servo control board. For the DCC user Servos can be accessory decoder operated. A special servo output on the accessory decoder is needed.

Long wire leads between servo and the control electronics can cause 'Servo Twitch' to occur which is mainly due to interference occurring in the long wire runs. This can be overcome though usually by twisting the servos operating wires together. Another way is to use an opto-isolator located at the position of the servo.
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Old 30-03-2017, 02:43 PM   #2
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Thank you, Flashbang. That is so very useful for me. Point motors are a 'to do' item for me, but that explanation means I know a bit more about what I'd prefer.
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Old 29-06-2017, 01:45 PM   #3
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Flashbang...thanks.
You stipulate a toggle switch but I want to make use of a dozen or so new DPDT slide switches to operate my tortoise motors.
It says in the destructions that although the switch is thrown " on" and the motor stalls. No damage can occur.
Can you please just clarify that I will be okay to use these slide switches.
They have two poles so I can cross over the wires on the two end tags and have the feed to the two centre tags.
The reason I am asking this is because there are toggle switches that spring back to centre " off" . Is this what you mean?
Is this a requirement?
Thanks
Pete
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Old 29-06-2017, 02:09 PM   #4
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Hi
Yes, a DPDT slide switch is fine with a Tortoise point motor or a standard analogue DCC Concepts slow motion motor.
It is not suitable for use with a solenoid motor or the DCC Concepts Digital slow motion motor though. Where only a momentary connection is used, hence the sprung to centre off toggle switches referenced.
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Old 29-06-2017, 02:39 PM   #5
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Thanks Flash Bang.
I have your book so rely on expert electrical advice .
I have just invested in six Tortoise motors, have done a quick test on them to see all works okay.
I must say that they, although hit my particular pocket a bit hard, are a good solid unit and on reading the instructions will be a breeze to instal.
Quite a brick though in size!
The US of A , has to be said, produce good kit .
You pays yer dollars an ya git what ya pays fer.
I have another query re wiring up a Peco double slip that seems to have so many points of view with regard to what gets isolated and what need not be, it becomes a head ache.
But I will refer this to another thread as this is inappropriate .
I will do a diagram first so to be explicit.
Thank you so much for your time.
Pete
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Old 11-09-2017, 09:08 AM   #6
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Default Switch clarification reqd

....... Wanting to use a mixture of solenoid ( fiddle yard) and slow action ( main track) point motors across layout with toggle switches throughout.

I think for the solenoids I need (on) - off - (on) type but SP or DP ?...... whilst for the slow action motors I think it is a locking type I should be using but is this is the on - off - on type and / or SP or DP ?

Can somebody pls clarify in simple layman terms - thanks
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Old 11-09-2017, 09:15 AM   #7
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The (on) - off - (on) type on both types of point motors SP for single points DP for cross overs where both points need to switch together......
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Old 11-09-2017, 10:03 AM   #8
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Quote:
Originally Posted by Tinker View Post
The (on) - off - (on) type on both types of point motors SP for single points DP for cross overs where both points need to switch together......
For solenoids a SP (on)-off-(on) is all you need. You can go with the DP option for a pair of points as Tinker says or you can stick with the SP and just add short jump leads between the appropriate terminals on the two point motors.

I only know what I have read on here about the stall type motors but presume that a SP would be more than enough. A DP would however allow you to switch something else at the same time if needed.
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Old 11-09-2017, 11:07 AM   #9
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I'll deal with this in the three main sections.. When using Toggle switches and motor operation for Analogue systems..
Solenoids types of point motors, such as Peco PL10 or PL11, Hornby R8014 and R8243, Seep PM1 to 4 range, Gaugemaster PM20 to name a few...
It is usual to use a non locking sprung to centre off toggle switch of SPDT (Single Pole Double Throw) type often referred to as (On)-Off-(On) where the bracketed (On) can't remain in the On position once the switches lever is released. A solenoid MUST only ever have a momentary pulse of power applied to its coils. Leaving power On to the coil for too long will very quickly burn that coil out and the motor then becomes useless.
However, there is no reason why one side of a DPDT (Double Pole Double Throw) (On)-Off-(On) type of toggle switch can't be used if that is all that is available. It makes no difference to the switch or motors operation.

Stall style of motors, such as the DCC Concepts Analogue Cobalt or Tortoise motor etc. These require a permanent feed to the motor which has the polarity of that feed reversed to drive the motor over to the other direction. Often 9v to 12v DC is used to feed them.
Assuming a DC power supply is being used then a toggle switch of the DPDT contact arrangement is used and the switch is of the On-On type. No Off position in the middle.
It is wired so as the two wires going to the motor are on the middle pair of wiring tags. The Positive and Negative DC feed wires are connected to one ends wiring tags together with a pair of short linking wires which their other ends are connected to the opposite pair of ends tags but they swap position so as feed left goes to other end right, feed right to other ends left tag. When the switch is one position, positive is fed for the motor on one wire and when the switch moves over negative then flows in that same wire. The other wire to the motor of course also swapping its polarity.

There are other methods of operating stall motors using split DC power supplies and SPDT switches or using AC a SPDT switch with diodes. But I'm not explaining these methods here.

Finally there are Servo motors. These use an On-Off SPST or a SPDT can be used but here with only one end and the middle contact are used. However the switch is not connected into the servo motors feed wires. It connects to a special Servo motor control circuit board and the switches are either left in their On or Off positions depending of what direction the Servo is to drive to. The controller board sends rapid pulses to the servo which moves and remains in the required position. Opening or closing the switches contact causes the circuits electronics to send operating pulses to the servo motor to move it to the other position and hold it in that position. The motor sends signals back to the control board to say where it is and the boards electronics adjust this as required.


This is a very brief and simplistic overview of the three operating systems using analogue switching. Though the Servo perhaps should be classed as leaning towards Digital operation and with some Servos is fully digital.
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Last edited by Flashbang; 11-09-2017 at 12:02 PM. Reason: Errors in typing and some content corrected
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Old 11-09-2017, 11:24 AM   #10
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Many thanks to all for the clarification - this all makes perfect sense now and apologises if as a rookie I have touched a subject that has previously been covered many times before..
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