Help with Point Motors! At wits end

[Pete the Elaner]

I am surprised nobody has mentioned this already, but Hornby's R044 works poorly with a CDU. Here is why:

 

SEEP point motors benefit hugely from a CDU because they are quite current hungry. I have tried them without & they barely move.

CDUs take time to re-charge. Half a second is usually enough to be useful.

Hornby's R044 is quite a simple switch. When throwing a point, it passes 2 contacts. The first one throws the point the way it is already facing, which is not very useful. The CDU discharges very rapidly across this coil.

If you continue throwing the switch with what I consider to be a normal action, it will pass the other contact (the one you want) before the CDU has had a chance to re-charge, so the CDU does not get given a chance to do its job properly.

 

There are 2 things you could try:

Throw the switch as normal. Wait a couple of seconds then move the lever a little towards the middle. The point(s) should throw with much more force.

Move the lever to the centre (it will have thrown the point in the wrong direction). Hold it in the centre for a couple of seconds for the CDU to re-charge. Continue throwing the lever. Now the CDU has had a chance to re-charge, it can discharge across the correct coil. This should make a massive difference.

 

Peco's 'passing contact' switch is a little more clever. It is a 2-way toggle with what I think of as a miniature 'anvil' which completes the circuit. Once the lever hits its end stop (& in in contact with the coil you want), it throws the anvil. This completes the circuit to throw the point then returns to its neutral position.

 

If you really want to use Hornby switches, then maybe you can use the 2-way switches with a push button to complete the circuit.

[JohnR]

14 minutes ago, ISW said:

John,

 

A couple of simple suggestions:

1. Is the hole in the baseboard large enough to allow the switch to the thrown to both extents of movement? Is there sufficient clearance to ensure the drive 'pin' is not contacting the sides of the hole?
2. With the PM1 at the 'middle' of its movement, is the turnout also at the middle of its movement? If the PM1 is 'offset' to one side it'll be able to move the turnout one way too much, but then only move it the other way not enough. This fits with your symptoms.

Ian

 

Thanks everyone for your kind and thoughtful assistance.

 

I have just refitted the PM1s, doing precisely as Ian has said (I used some bits of cardboard as chocs between the point blades, and a piece of cardboard fitted between the solenoid coils with a hole in the centre for the drive pin.

 

The baseboard was on its side so I could have relatively easy access to both sides (its only 225mm wide!). 

 

I fitted one motor. Then tested it. It seemed to work in both directions, consistently, with a pause in between throws.

 

Then I fitted the second (one of the 3-way motors). It too seemed to throw in both directions consistently.

 

Then I fitted the third (the other 3-way). It was more tricky - there doesnt seem to be much travel on the 3-way blades compared to the standard points. But it too, seemed to be working. 

 

I gently turned the board upright. 

 

I tested the Peco PL11 - it worked.

 

I tested one PM1 - it worked one way. But not back (you could hear the thud of the solenoid, the rod vibrated, but no movement of the point).

 

I then tested the other two, and had similar results.

 

And then the Peco PL11 decided to do the same. Again you can hear the thud of the tiny solenoids, but no movement of the throw bar hooped over the tie bar of the point.

 

 

 

 

[smokebox]

If the point motors are screwed to the baseboard, try loosening the screws very slightly.  Overtightening will cause problems.

 

PS.  Some Peco CDUs are a bit weak, early ones especially, later ones are saidto be better.

Edited February 19, 2021 by smokebox

[kevinlms]

4 minutes ago, JohnR said:

 

Thanks everyone for your kind and thoughtful assistance.

 

I have just refitted the PM1s, doing precisely as Ian has said (I used some bits of cardboard as chocs between the point blades, and a piece of cardboard fitted between the solenoid coils with a hole in the centre for the drive pin.

 

The baseboard was on its side so I could have relatively easy access to both sides (its only 225mm wide!). 

 

I fitted one motor. Then tested it. It seemed to work in both directions, consistently, with a pause in between throws.

 

Then I fitted the second (one of the 3-way motors). It too seemed to throw in both directions consistently.

 

Then I fitted the third (the other 3-way). It was more tricky - there doesnt seem to be much travel on the 3-way blades compared to the standard points. But it too, seemed to be working. 

 

I gently turned the board upright. 

 

I tested the Peco PL11 - it worked.

 

I tested one PM1 - it worked one way. But not back (you could hear the thud of the solenoid, the rod vibrated, but no movement of the point).

 

I then tested the other two, and had similar results.

 

And then the Peco PL11 decided to do the same. Again you can hear the thud of the tiny solenoids, but no movement of the throw bar hooped over the tie bar of the point.

 

 

 

 

Are you 100% sure that the point motors are quite square with the tie bars? Your symptoms describes what happens if they are not exactly in line. SEEP's are VERY fussy on this.

 

I'd still be interested to know what the DC voltage is out of the CDU.

[Nick C]

Here's what I did on a previous layout with SEEPs:

 

 - Support the layout on it's back to make it easier to get to both sides.

 - drill a small hole (track pin size) through the baseboard at each end of the tie-bar

 - draw a line underneath passing through both holes - this effectively mirrors the alignment of the tie-bar underneath.

 - wedge the points in the mid-position with a couple of coffee-stirrers

 - position the motor in the mid-position

 - align the motor using the line drawn earlier

 - screw the motor into position

 - remove the wedges, test manually to make sure the motor and point move freely

 - wire up the motor and test 

 

I just used sprung centre-off toggle switches for that one, and a stand-alone 16v power supply.

[JohnR]

4 minutes ago, smokebox said:

If the point motors are screwed to the baseboard, try loosening the screws very slightly.  Overtightening will cause problems.

 

PS.  Some Peco CDUs are a bit weak, early ones especially, later ones are saidto be better.

 

They are screwed to a mounting ( here ) .

 

The CDU claims to be a Mk2, but I have not been impressed.

7 minutes ago, kevinlms said:

Are you 100% sure that the point motors are quite square with the tie bars? Your symptoms describes what happens if they are not exactly in line. SEEP's are VERY fussy on this.

 

I'd still be interested to know what the DC voltage is out of the CDU.

 

I have to admit to not being 100% sure. However, I have viewed the hole in the tie bar from the underside of the board, through the slot in the mounting, and you can clearly see the hole at both ends of the throw, and it (the slot) *appears* to be in alignment. The instructions said to do this from above (marking the throw of the tie bar), but I had already laid my track.

[Theo]

To centralise Seep point motors I insert offcuts of plasticard in the point blades, and a homemade wire clip to centralise the point motor. Its then easy to insert the operating wire from underneath and attach the motor to the baseboard.  (See attached photos). I've always used double-side foam tape successfully, which can be removed easily if the motor proves faulty.

[JohnR]

8 minutes ago, Nick C said:

Here's what I did on a previous layout with SEEPs:

 

 - Support the layout on it's back to make it easier to get to both sides.

 - drill a small hole (track pin size) through the baseboard at each end of the tie-bar

 - draw a line underneath passing through both holes - this effectively mirrors the alignment of the tie-bar underneath.

 - wedge the points in the mid-position with a couple of coffee-stirrers

 - position the motor in the mid-position

 - align the motor using the line drawn earlier

 - screw the motor into position

 - remove the wedges, test manually to make sure the motor and point move freely

 - wire up the motor and test 

 

I just used sprung centre-off toggle switches for that one, and a stand-alone 16v power supply.

 

 

Thanks Nick. In the event of me using SEEPs on a future layout, I will definitely do that. However, I have had to hack a hole in the baseboard for the SEEP mounting, which is now glued to the underside of the board. I did use that wedges to get the point and the motor into the central position before fixing them.

[spikey]

1 hour ago, MR Chuffer said:

Yes, off Amazon and other electrical suppliers, I ordered 10 Mini (On) Off(On) Momentary Toggle Switch Miniature SPDT  - £4.65. I'm not using a CDU though, and not planning to, but not sure that it makes a difference.

 

And yes, these were any old SPDT switches....

 

A switch is either an ordinary ("any old") SPDT switch or it is a momentary SPDT switch.  I have nothing further to say.

[MR Chuffer]

21 minutes ago, spikey said:

I have nothing further to say.

Excellent, good news indeed!

[Theakerr]

First, is the problem in the same direction for each set of points?  Just define one direction as push using say an edge of the baseboard as a datum and the other is pull.  Then see if the problem is common to one action.   This will not necessarily tell you what the problem is but now you will be able to eliminate some circuits.  Next are you using a common ground?  If you are you have again eliminated one possible problem because they work in one direction.  Next, do your points have the springy thing under the switch blade that is supposed to contact the contact rail to improve the electrical connection?  If they do make sure it has not been raised up so as to prevent the switch blade from going all the way across.  This can be deceptive in that when moving the points manually they appear free because the finger holds the blade down whereas the point motor can/tends to slightly raise the tie bar and the blade with its attached spring just a bit.  For whatever reason I have found that if this is a problem it tends to be when throwing from the curved side to the straight side.  Finally, as someone else has said check how tight the points are fastened down and what is under the point tie bar.  For my hidden sidings that are laid directly onto a painted wood surface I have put a bit of grease proof paper under the tiebar in effect to lubricate it.   Every so often i have to replace it because normal dust etc cause it to become 'sticky'. 

[Pete the Elaner]

16 hours ago, MR Chuffer said:

Yes, off Amazon and other electrical suppliers, I ordered 10 Mini (On) Off(On) Momentary Toggle Switch Miniature SPDT  - £4.65. I'm not using a CDU though, and not planning to, but not sure that it makes a difference.

 

And yes, these were any old SPDT switches....

 

A CDU can make a massive difference, but there is no need to fit one straight away. You can always add it later if required. I was surprised at how much they can help.

 

I saw in a previous post that you are using SEEP motors. I have found these need a bit more powerful burst than Peco motors & when fitted to a friend's layout, we needed to fit one before the points would throw. They tried without one, but would not actually move, so we fitted one. I was surprised at how much difference it made.

The layout has been doing exhibitions for several years & each point has thrown first time every time with no failures of motor or switch.

 

Some club members complained about their Peco CDU lacking power so I gave them one I had built myself & they were happy that it worked better. I had used CDUs as a small project to help others with their soldering.

Mine cost about 1/3 of Gaugemaster's, but it looked rather amateur! I thought I could built it cheaper but the capacitors are the expensive components. They are also the crucial ones though.

Gaugemaster's CDU is well built & I feel it is good value for money.

 

A CDU does 4 things:

 

Throws points more positively

Protects against motor burn-out

Prolongs the life of switches

Allows the power supply to also be used for layout lighting with no dimming when the points are thrown

 

But with all things there are drawbacks:

 

The throw can be too fierce for delicate hand-built points

It is an added cost

It is an extra component to wire in.

 

This post is long enough already. There was an article in DOGA's journal about it a while back which explains how & why they work, so I'll attach it. I am sure the author will not mind 

The Benefits of a CDU.pdf

[JohnR]

Thanks everyone, once again. 

 

I think I have some light at the end of the tunnel (as long as its not a train coming in the opposite direction!)

 

I tried them all again this morning. But leaving long gaps between throws. They all seem to work, as long as I leave 10 seconds between each throw. This seems a long time, so once my multimeter arrives today, I shall test the 16v AC output on the controller. 

 

My assumption - and please correct me if you think this is wrong - is that the 16vAC output is not as strong as it should be. Hence why the points had issues when connected directly to the ac output. And its now taking a long time to recharge the CDU - I believe it should only take a second or two?

 

Assuming it is that the 16v ac output on the GM Combi is at fault (or at least inadequate), would it be worth getting a separate power supply? And if so which one?

Edited February 20, 2021 by JohnR

[Golden Eagle]

FWIW, I have gone through exactly the process over recent weeks, building a MPD using PM1s, Hornby switches and a Gaugemaster controller for exactly the same nostalgic reasons you describe! (A bank of Hornby switches is what my grandfather had, so is clearly the "right" way to go about it)

 

As others have mentioned, the SEEPs are incredibly fussy about positioning and orientation. Normal turnouts are bad enough - double slips are a nightmare (as threads which I subsequently found had previously noted!) - I have managed to make one double-slip work...a second I have given up on (after having honeycombed the bottom of the baseboard trying to fix the motor in a position that it works) - I'm going to put surface mounted motors on that double slip!

 

However, there are some points that I want to move as a pair (and in the case of my three-way, the need to be able to fire both motors at the same time to move directly from left-to-right and vice versa). There wasn't enough "oomph" for this from my controller. I picked up an RK cdu1 CDU kit for less than £5 delivered. It took <10min to build and recharges fast enough that moving the Hornby switch requires only a brief pause in the centre of the movement. It has a helpful LED which illuminates when charged.

 

Not sure how long the Peco CDU should take to charge, but various threads suggested that it was a bit gutless...and the RK unit was significantly cheaper.

 

Anyway...(and forgive me if this is teaching you to suck eggs)...how do you plan to test your AC outlet?

 

Simply plugging a multimeter into your AC outlet will (probably) show 16V AC as there is no load drawing current. (If you're not getting 16V AC, you've found your problem). If the SEEPs are drawing more current than the unit can supply, this will drop the voltage as current flows...however, using a momentary switch, the time for which the current flows is so short that you're unlikely to see the effect on a digital meter (on an analogue, you might see some deflection of the needle).  If you don't use a momentary switch, you will see any drop in output voltage...but risk burning out the solenoid.

 

I've just measured the resistance of some spare SEEPS - the coils are ~2ohms, so you're looking at drawing (roughly) 8A and needing to dissipate around 128W, so simply wiring in a small 2ohm resistor (typically <0.5W) will fry the resistor in very short order. I'm guessing that if you didn't have a multimeter, you're unlikely to have high power resistors sitting around...

 

(If anyone does know an easy way to test the 16V AC power outlet, please educate me!)

[kevinlms]

1 hour ago, JohnR said:

Thanks everyone, once again. 

 

I think I have some light at the end of the tunnel (as long as its not a train coming in the opposite direction!)

 

I tried them all again this morning. But leaving long gaps between throws. They all seem to work, as long as I leave 10 seconds between each throw. This seems a long time, so once my multimeter arrives today, I shall test the 16v AC output on the controller. 

 

My assumption - and please correct me if you think this is wrong - is that the 16vAC output is not as strong as it should be. Hence why the points had issues when connected directly to the ac output. And its now taking a long time to recharge the CDU - I believe it should only take a second or two?

 

Assuming it is that the 16v ac output on the GM Combi is at fault (or at least inadequate), would it be worth getting a separate power supply? And if so which one?

Something is wrong, if it takes 10 seconds to charge up sufficiently.

 

I don't know what's in the Peco one, but most CDU's include a transistor which speeds up the charging time.

[JohnR]

Thanks for that Golden Eagle, a  lot of it makes sense. 

 

My understanding of the Hornby switches - from Brian Lambert's website - is that you only need a moment's pause to use the R044 switches with a CDU, presumably it is only supposed to take a moment to recharge a decent CDU? Either the Peco CDU is a Lemon (another mistake buying that!) or the power supply is weak in taking so long to recharge it?

[JohnR]

7 minutes ago, kevinlms said:

Something is wrong, if it takes 10 seconds to charge up sufficiently.

 

I don't know what's in the Peco one, but most CDU's include a transistor which speeds up the charging time.

 

I havnt timed it with a stop watch, but rather counted the seconds out loud. A gap of 5 seconds seems to never work. 10 works most of the time (one of the 3-way's motors seems to need a little longer).

 

Either way I think it is too long?

[Michael Hodgson]

20 hours ago, Pete the Elaner said:

I am surprised nobody has mentioned this already, but Hornby's R044 works poorly with a CDU. Here is why:

 

 

What he said.

 

Those switches were designed many decades ago for throwing the old Triang solenoid point motors, running them from the 15v AC auxiliary output that most contemporary power packs had.  They are fine if that's what you are using.   They give a momentary burst of fairly hefty power to the irrelevant coil then to the one you want to activate.  They are called passing contact switches because they only make contact whilst the lever is being moved and don't leave the power on continuously at either end of the lever movement - that would burn out the solenoid.

 

A CDU is a much more modern idea and is designed to deliver a momentary burst of stored power but is triggered by a much lower current.  They can be triggered using a bell push or similar for points normal and another for reverse.  The problem with using R044 switches with a CDU is that you are discharging the stored power (into the irrelevant coil) just before you want to apply it to the coil that you intend to fire.

 

So I would use either a CDU or the passing  contact switch but not both.

[Pete the Elaner]

2 hours ago, JohnR said:

 

My assumption - and please correct me if you think this is wrong - is that the 16vAC output is not as strong as it should be. Hence why the points had issues when connected directly to the ac output. And its now taking a long time to recharge the CDU - I believe it should only take a second or two?

 

 

It sounds more like the CDU than the power supply.

 

I have not used a Peco CDU myself but several club members seemed very unimpressed with the one they had & it seemed very lightweight. I wanted to dissect it to find out what is actually inside, but it is stuck at the club right now & I cannot get to it for obvious reasons.

If it turns out to not be a good purchase then do not treat this as a mistake. A mistake is repeating something you know does not work.

I have used the Gaugemaster CDU & can recommend it. It recharges quickly & provides a nice positive throw.

[Pete the Elaner]

50 minutes ago, Michael Hodgson said:

 

So I would use either a CDU or the passing  contact switch but not both.

 

I don't think a passing contact switch will work.

My experience of SEEP motors is that they are a lot harder to shift than older Hornby motors & need a CDU for reliable operation.

[JohnR]

 

 

1 hour ago, Michael Hodgson said:

What he said.

 

Those switches were designed many decades ago for throwing the old Triang solenoid point motors, running them from the 15v AC auxiliary output that most contemporary power packs had.  They are fine if that's what you are using.   They give a momentary burst of fairly hefty power to the irrelevant coil then to the one you want to activate.  They are called passing contact switches because they only make contact whilst the lever is being moved and don't leave the power on continuously at either end of the lever movement - that would burn out the solenoid.

 

 

21 hours ago, Pete the Elaner said:

I am surprised nobody has mentioned this already, but Hornby's R044 works poorly with a CDU. Here is why:

 

Thanks both, and the ability (or lack thereof) a Hornby R044 switch to work properly (or at least without a pause mid-throw) was why I changed to Peco PL26 switches, as I said in my original post. I felt that since the PM1s wernt throwing themselves properly with the direct 16v ac supply, that a CDU would help. Hence why I changed the switches.

[Retro_man]

I would definitely check that each motor worked correctly before trying to install it under the baseboard.

In this case I may even go so far as to make a test assembly with a point on a piece of board so I could see what is happening top and bottom sides simultaneously.

 

Steve

[Michael Hodgson]

1 hour ago, Pete the Elaner said:

 

It sounds more like the CDU than the power supply.

 

I have not used a Peco CDU myself but several club members seemed very unimpressed with the one they had & it seemed very lightweight. I wanted to dissect it to find out what is actually inside, but it is stuck at the club right now & I cannot get to it for obvious reasons.

If it turns out to not be a good purchase then do not treat this as a mistake. A mistake is repeating something you know does not work.

I have used the Gaugemaster CDU & can recommend it. It recharges quickly & provides a nice positive throw.

I too have my doubts about the CDU - it shouldn't take more than half a second or a second the recharge.  However if you operate a R044 at anything like a normal speed it will be too fast for the CDU to recharge between its first contact and the second.

I don't have experience of the Peco CDU myself, but I haven't had any trouble with other commercial CDUs other than when trying to move three points simultaneously off a single CDU (not a recommended approach) - the problem with that was the slight difference between point motors was enough for one of them to take more of the stored charge than the others.

[kevinlms]

11 minutes ago, Michael Hodgson said:

 the problem with that was the slight difference between point motors was enough for one of them to take more of the stored charge than the others.

That isn't anything to do with a CDU, but our old friend Ohms Law.

If one point motor has a lower resistance, it will take the lion's share of the current.

[Michael Hodgson]

35 minutes ago, kevinlms said:

That isn't anything to do with a CDU, but our old friend Ohms Law.

If one point motor has a lower resistance, it will take the lion's share of the current.

Quite so.