MP1 Point Motor Problem

[Baconbutty0]

I have used MP1 point motors on Peco 009 12 inch points without any problems.  On my new layout I am using 009 mainline 18 inch points.

I am getting a momentary short circuit when the point motors operate.  It seems the stiffness in the point latch mechanism is giving a bit of flex between the tie bar and the motor so that the MP1 contacts change slightly ahead of the point blades breaking rail contact, hence the short.  Tried moving the motor position slightly but this makes no difference.

Has anyone else experience this and if so how did they solve it?  At the moment it would seem that the answer would be to remove the latching mechanism, unfortunately this mean a virtual strip down of the laid track.

Ollie.

[Graeme Dunbar]

I've not had that problem with the MTB MP1 point actuator, but possible solutions might be to remove the over-centre spring or to use a stiffer actuator wire if it is flexing too much.

I guess there might be a slight chance the actuator was not manufactured correctly and the phasing of the wire movement and the switch operating is out. Do you have a meter and can measure when the switch changes over with respect to the movement when the actuator is removed from the point so that it is under no load?

[Ian McAulay]

I've not had that problem with my MP1 motors, but I've only used them on 12" radius points.

On my more recent installations, I have removed the over-centre spring from the points. All is not lost if the track is already fixed down - I forgot to do it on one of mine but discovered that there was enough of a gap beside the tiebar that I could get the point of a fine pair of tweezers to the spring and haul it out. This is not elegant engineering but it works! I've not used the 18" points, so I don't know if the same trick works.

Ian

[B.Meldon]

They are expensive point motors!!

[Graeme Dunbar]

They are expensive point motors!!

It depends how you look at it. About £18.

The Peco Twist Lock is about £15 plus £9 for the microswitch.
The Peco side mount version is about £10. Not sure if it is possible to fit a microswitch.
The standard Peco version is about £9 and the same for the microswitch. The base if wanted is another £5.

For the solenoid actuators a passing contact switch is maybe 9 or 10 pounds, or a CDU could be used or pen and stud made to save money.

I'm sure shopping around these prices could probably be bettered, but not by much I suspect.

The MP1 point motors are slow action, have built in microswitch, built in "X and Y" screw position adjustment, need just a low cost and low current DC supply (e.g. cheap wall wart) and are operated using an inexpensive SPDT, i.e. changeover switch, maybe under £1. They also include convenient screw terminal connections.

The only concerns I've come across is someone who apparently got a rogue batch where some of them were not up to scratch. I've not bought one for a while but I presume they have sorted their manufacture out.

Edit: also the tie-bar throw can be adjusted to suit different scales.

[Ian McAulay]

I went through the same logic regarding pricing as Graeme has set out. Also, at the time I chose to use the MP1 motors, Peco only offered completely open microswitches, which I don't really like (dust accumulation and risk of mechanical damage).

You can run the MP1 motors off AC as well. I've done that on my return loop modules, which have precisely one turnout each and have local controllers, so have a 16V AC feed available. They are possibly a bit noisier than on DC (half wave rectification) but not significantly so.

Ian

[Graeme Dunbar]

I forgot they would run off AC as well as DC. That's interesting to hear that they are a bit noisier on AC, though that sounds reasonable. The data says they will run of quite a range of voltages too (9 V to 16 V) and draw about 150 mA.

They are certainly a big step up from the Fulgurex/Lamaco ones or the Hoffmann/Conrad ones and less expensive and smaller that Tortoises. I've not tried Cobalt motors.

[B.Meldon]

Slow motion is all about personal choice. In the real world the point blades on most narrow gauge lines move across very fast indeed and do not move in 'slow motion' at all!

I can see what you are on about regarding the price.
That said I can not remember the last time I paid full price for a PL10. There are usually lots of new old stock or good second hand ones on e-bay, in local model shops or on the 009 society sales stand. I keep several spares and tend to get them when they are cheap for use at a later date.
The last batch of 10 were £1 each!
I use the PL-13 accessory switches these are about £6 new.
But again are often available as new old stock for a lot less.
The switches I use are home made using brass strip and 5 8ba nuts and bolts. But center off sprung momentary SPDT (On)Off(On) toggle switches are only about £1 each.
The capacitor discharge units are indeed about £7.50.

In over 40 years I have never had any point damaged by a solenoid point motor.
I have had a couple of the steel pins snap on the PL10's, but as I have made them all easy to replace, in both cases it was a 15-min fix to replace the motor and I always have a spare with me at exhibitions just in case.

[Ian McAulay]

I forgot they would run off AC as well as DC. That's interesting to hear that they are a bit noisier on AC, though that sounds reasonable. The data says they will run of quite a range of voltages too (9 V to 16 V) and draw about 150 mA.

I metered the current on one when I first started using them. I think it was just over 100mA on DC, but that was a sample of 1 and it was pre-installation, so not driving anything! It's low enough current that you don't have to worry about the 750mA rating of a Gaugemaster wall wart.

They are certainly a big step up from the Fulgurex/Lamaco ones or the Hoffmann/Conrad ones and less expensive and smaller that Tortoises. I've not tried Cobalt motors.

I used to use Fulgurex motors on 2FS. Nice and slow but so powerful that they could rip the tiebar off a soldered point if the point hit its limit before the motor did! I was very careful about point linkage after that!

I've used Cobalt in 00. Nice action but I think I would use MP1 (or other MTB models) now (I hadn't discovered them at that time). The main disadvantage is the enormous depth you need under the baseboard to accommodate Cobalt motors, or use an adaptor to turn them sideways (but they're still fairly bulky that way round).

[Hugh Norwood]

{I really must get a MP1 to have a play!}