Identifying a Cobalt Point Motor

[Tony Davis]

I bought the Cobalt point motor recently as part of a job lot, I was really interested in the Gaugemaster T1 which it was paired with. I had, up until yesterday, assumed that it was a DCC thing, but on reading a thread about changing polarity with a microswitch I found out this isn't neccessarily the case.

 

So, I dug the point motor out to see if had any identifying markings on it, which, apart from DCC Concepts, it doesn't.

 

I am appealing to you for help, and have attached some photo's which may assist.

 

I would also like to know if it is possible to do a test - "off layout" to find out if it works or not.

 

Many thanks,

 

Tony

 

 

 

[Danemouth]

Looks like the original Cobalt as used on Danemouth!

 

Connect 9v DC to the terminals at each end - that should cycle the motor. If it doesn't reverse the polarity. Cobalts change when the polarity is reversed.

 

Dave

[newbryford]

I'm with Dave - it's an original analog Cobalt.

8 terminal Cobalts are either original analog or Digital motor - the Digital usually has a sticker with the terminals on, as well as marking on circuit board on the rear of the terminal block

 

The full manual is here: https://www.dccconcepts.com/manual/owners-manual-cobalt-classic-point-motors/

 

The important bit is on page 8.

 

Go with 9v (or 12 v with a 270-330 ohm resistor)

Some of the accessory outputs on the side/back of controllers - although rated at 12v, can be much higher (16v isn't uncommon) with no or little load on them.

 

Cheers,

Mick

 

[Brian]

I agree It looks like an early standard Cobalt.  Connections 1 & 8 are or the operation - apply 9 to 12 volts DC to them and the motor will move one way, reverse the power and it moves back the opposite way. Terminals 2 to 7 are the two pairs of electrically separate internal change over contacts used for things like frog polarity switch, panel LED indications, signal aspect control or whatever needs switching by the points position. Common switch connection is on terminal 4 to 2 & 3 and terminal 5 to 6 & 7. 

 

Edit... Beaten to it by Newbryford :-)

Edited August 15, 2018 by Brian

[Tony Davis]

Thank you all, I will give it a try later on.

 

BTW, are the foam mounting pads really neccessary?

[newbryford]

Thank you all, I will give it a try later on.

 

BTW, are the foam mounting pads really necessary?

 

The foam can give some degree of noise insulation - but if foam is fitted and the screws are anything other than loose, then this negates the foam...…

 

I've fitted foam pads to mine, used the screws to make sure everything is in place and then slackened them off a day later so that they're actually doing nothing. BTW - the adhesive on the foam is quite strong and resists removal......

 

Cheers,

Mick

[Tony Davis]

Thanks Mick

[Tony Davis]

It worked, thank you, now for the fun of removing the old solenoid point motors and retro-fitting Cobalts

[Brian]

Hi

Don't forget the solenoids used a pulse of power and the Cobalts will need a continuous supply to their operation terminals.

You cannot use a CDU with a Cobalt either.

Ideally you'll need a separate power source of around 9 volts DC and you'll need to change the existing point switches from momentary type to continuous On type.  i.e. On-On type of the DPDT variety, where the polarity going to the Cobalt is flipped over by changing the switches position. Unless you wish to use diodes to rectify an AC power supply, then SPDT switches can be used.  But IMO this involves more work and the simplest is the DPDT On-On switch and good regulated DC power supply.

Edited August 16, 2018 by Brian

[ChrisG]

The foam can give some degree of noise insulation - but if foam is fitted and the screws are anything other than loose, then this negates the foam...…

 

I've fitted foam pads to mine, used the screws to make sure everything is in place and then slackened them off a day later so that they're actually doing nothing. BTW - the adhesive on the foam is quite strong and resists removal......

 

Cheers,

Mick

 

 

Just to say, I have found the adhesive pads to be utterly useless as they cannot support the weight of the motor, at least when attached to plywood. 

 

 

Chris

[newbryford]

Just to say, I have found the adhesive pads to be utterly useless as they cannot support the weight of the motor, at least when attached to plywood.

 

 

Chris

I find that quite odd. Has the pad split or adhesive let go? If the plywood is clean, or even better varnished or painted, it can take quite a bit of persuasion to remove a motor that has been mounted with the pads. In one case, there was wood stuck to the pad afterwards.

Cheers

Mick

Edited August 16, 2018 by newbryford

[Tony Davis]

Hi

Don't forget the solenoids used a pulse of power and the Cobalts will need a continuous supply to their operation terminals.

You cannot use a CDU with a Cobalt either.

Ideally you'll need a separate power source of around 9 volts DC and you'll need to change the existing point switches from momentary type to continuous On type.  i.e. On-On type of the DPDT variety, where the polarity going to the Cobalt is flipped over by changing the switches position. Unless you wish to use diodes to rectify an AC power supply, then SPDT switches can be used.  But IMO this involves more work and the simplest is the DPDT On-On switch and good regulated DC power supply.

I was planning on using a MERG 16v AC to 12v dc supply kit (replacing the 7812 with a 7809 and a suitable heatsink) the kit uses a bridge rectifier, is this what you mean by using diodes to rectify the AC current?

[Brian]

Hi,

That will work and you will need DPDT switch.

I was referring in the last part of my previous repy to the use of an A.C. power source where two diodes are used to provide half wave rectification and then SPDT toggle switches are used.

 

The AC methods of switching and power source are shown on the Circuitron Tortoise web sites.

Example of using an A.C. supply and two diodes... link to wiring

Edited August 19, 2018 by Brian

[Tony Davis]

Thanks Brian