Low energy Peco point motors

[ColinB]

Any idea why Peco has discontinued the low energy PL 10 point motor? I would have thought these would be more suitable to the digital age drawing less current, but I assume they didn't sell well.

[The Duke 71000]

Never fit solenoid mechanisms to Peco's points (or any others for that matter) they end up breaking the tiny hair spring between the blades, due to the constant hammering. Then of course you'll need a motor drive mechanism such as Fulgurex to continue working the point, or you'll have to throw the point away !

 

 

Might as well take the hair spring out to begin with and use a Fulgurex motor drive from the outset. You even get 2 free switches on these mechanisms. Means you could interlock your signals with the point as in real life !!!

 

 

Some of my Fulgurex mechanisms are now 30 years old, having been fitted to more than one heavy duty exhibition layout and all still going strong. Fulgurex of Lusanne Switerland. Rolls Royce products !!

 

The Duke 71000 - 95mph through Tiverton, 7% cut-off and the regulator nearly closed. It's a walk in the park.

[Going Spare]

PL-10W and PL-10WE are still showing on Peco's website.

[ColinB]

I have close to 60 points on my layout, so Fulgurex is not an option. Anyway the PL10 is probably the most efficient way of driving the point, if it is mounted as part of the point. As for the springs, they go without having the point motor, generally it is clip holding it that becomes loose. The Suppliers I looked at implied that Peco were discontinuing them. On Hattons website it says "This point motor is now discontinued from Peco's range" so unless someone is not telling the true, I assume Peco are just running out what they have left.. 

[96RAF]

Surely asking the question of PECO would get you to the truth, rather than rely upon quesswork and speculation.

[ColinB]

Sorry RAF96 I thought  the idea of a chat room was to discuss topics and it might be very important to somebody thinking of using them. I just thought somebody on here might know. As for contacting Peco, my last request for data about code 75 rail has been unanswered for nearly two weeks and that was a just a question about what sort of code 75 would be applicable to fit with my turntable. Peco probably wouldn't answer the question of why they they are discontinuing an item, firms don't generally do that. I know Ford changed certain items on a car because the Head of Engineering changed, but they are not going to tell you that. It is not a real issue to me, it just seemed with more computer control, the low version type would be the future. Interestingly most of the clone types "Hattons", "Gaugemaster" are the low energy types. As for the code 75 rail, I took a flyer whilst on holiday and bought just the ordinary code 75 stuff. I suspect that they probably didn't sell many as it seems not many people knew they existed, I only found them by chance when going through one Suppliers website, sadly most of the Suppliers search engines don't always pick them up.

[ColinB]

I think I may have answered my own question. I bought some low power point motors and basically have found that they don't generate the same force as the original PL10. I only noticed it as I was fitting them to new points, that were a bit stiff. So probably the reason they don't work very well with the Hornby accessory module as Chrissaf was saying, is nothing to do with the accessory module, it is just that they are not that powerfull. That probably explains why they are withdrawing them., they basically don't work very well.

[96RAF]

As the Yanks say Colin there ain’t no substitute for horsepower.

Unfortunately you have a two edged sword .... Lo-power motors take less oomph to drive them, but then they don’t have the kick to do the job. Motors powerful enough to do the job reliably take a lot of driving and can be brutal to your points mechanisms if not correctly installed.

Someone must be able to engineer a decent quality, compact, reliable and cheap point motor that is dead simple to install (clip on?) and simply works as advertised. Some of the motor drive units are huge and/or cost a fortune. The price of a simple solenoid can be disproportionate to the ancient engineering principle and parts. Add to that the cost of necessary switching if DC or an interface decoder if DCC.

[ColinB]

I only tested them at 15 volts AC, as I test them before I install them, so I don't know if they will work better with the CDU system which has a slightly higher voltage. That does explain why one I installed about a year ago only pulls one way now. I know a lot of the modern stuff we used on cars got smaller and smaller, but then Ford spends millions on development, I doubt Peco has that sort of money. So it looks like it is back to the PL10s with a relay board, fortunately an 8 channel one from China is cheaper than buying the parts and making it myself. The low power PL10s appear to be double the impedance of the ordinary PL10. 

[Chrissaf]

Colin, I'm glad that you have come to that conclusion yourself. I was reluctant to propose my theory [to your original question] below based on my experience earlier in this thread, as that would just have promoted a 'ping pong' round of 'to and fro' dialogue that would ultimately just go round in circles and get nowhere fast.

 

But now that you have come to the same conclusion as me ... I can now document the basics of my theoretical assessment of the 'Low Energy' PL-10 versions ... based upon my practical experimentation.

 

First of all, let us assume that the mechanical force needed to throw a point reliably is constant regardless of what point motor is used. This mechanical force requires a certain level of point motor power to operate the point. This is the premise of your own statement in your reply above.

 

Now in reality point motors are inductors so you can't accurately calculate volts, current and power using Ohm's Law. But if one only considers the instantaneous point in time at turn on, then Ohm's Law gives a reasonable estimate before the effect of inductance and back EMF's takes over.

 

The measured DC resistance of a PL-10W is 11.4 Ohms whilst the standard PL-10 is nearer 4 Ohms.

 

Let us assume at this stage, analogue operation of the point motors with an operating voltage of 18 volts DC.

 

At the instance of switch on using a PL-10 (4 Ohms) the current will attempt to rise to [Current = Voltage / Resistance] which equals 18/4 = 4.5 Amps = [4.5A x 18V] 81 WATTS.

 

I think that we can all agree that operating a PL-10 with an 18 volt DC supply gives very robust operation.

 

Now consider the same PL-10 operation using a DCC Accessory Decoder where the output is 14 volts DC.

 

At the instance of switch on using a PL-10 (4 Ohms) the current will attempt to rise to [Current = Voltage / Resistance] which equals 14/4 = 3.5 Amps = [3.5A x 14V] 49 WATTS.

 

Although the operation of the PL-10 under DCC control is nearly half the power compared to 18 volts DC [49 versus 81 WATTS], the operation is still reasonably robust.

 

Now consider the same using the PL-10W

 

At 18 volts DC, the instance of switch on using a PL-10WE (11.4 Ohms) the current will attempt to rise to [Current = Voltage / Resistance] which equals 18/11.4 = 1.57 Amps = [1.57A x 18V] 28 WATTS.

 

Using the PL-10WE in an analogue way [18 volt DC supply] does indeed use less power that the PL-10. That is to say 28 Watts versus 81 Watts [theoretical comparative estimates]. Hence the 'Low Power' product description is perfectly valid for PECO to state.

 

But now consider operating a PL-10WE under 14 volt DCC control.

 

At the instance of switch on using a PL-10WE (11.4 Ohms) the current will attempt to rise to [Current = Voltage / Resistance] which equals 14/11.4 = 1.22 Amps = [1.22A x 14V] 17 WATTS.

 

This is nearly half again the power under Analogue 18 volt operation. And I found that this was just too low to operate the PL-10WE reliably using the Hornby R8247 [14 volt DC output] Accessory Decoder.

 

At the start of this reply I mentioned experimentation.

 

My experiments that support my theory were based on the following set up.

 

• Firstly I attached a PL10WE to a PECO point on the test bench.
• I connected my variable 2.5 Amp Bench Power Supply to a stand-alone CDU and temporary toggle operation switch. I used the CDU to supplement the 2.5 Amps of the Bench PSU.
• I then used the variable Bench Supply to test operation of the point motor using the 14 volt DC to 20 volt DC range in 1 volt steps.

 

I did the above first with a PL-10WE and then again with a PL-10 and compared results. Currents could not be measured because of the pulse nature of the test using a CDU, so the results were subjective observations of point operation.

 

For the PL-10, adequate operation was seen at 14 volts DC, but as expected ... as the voltage went up, the operation got more robust.

 

However, for the PL-10WE the point would just not throw at all at 14 volts DC, operation was weak at 16 volts DC but adequate at 18 volts DC and very robust at 20 volts DC.

 

My conclusion, is that the PL-10WE consumed less current (based upon maths theory rather than measured values) and thus less power [as advertised by PECO] at all voltages, but still needed significantly higher voltages than the PL-10 to operate reliably, and voltages significantly higher than the voltages generated by the Hornby R8247 Accessory Decoder.

[ColinB]

Thanks Chrissaf for the data, I am not an expert on solenoids, I need to go and do some reading. I think they assumed by doubling the number of turns on the coil they would get the the same effect. The thing is if you load it up with one of their slider switches that fit under the motor it would never work, even with a PL10 there are issues, that is why I use microswitches. The thing I cannot get my head around surely they did the same tests you did before marketting it.

[Buz]

Hi Guys

First up never destroyed a point with a twin-coil solenoid yet be it an old Hornby Type or Peco type.

18v seems a little high I use nominally 16V with a CDU to operate mine which seems to be the normal recommended accessory feed and extra for analogue which I use there are exceptions I know.

I would have thought that the DCC Witchcraft had its own recommended style of point motor it seems to have its own everything else that is different and three times more expensive to set up, and no one seems to get  it even with the spell book to make it work.

I really don't think the power consumption from our toys makes a lot of difference in the overall scheme of thiing's

As far as I know PL10's are still available if not it will be a lurgy Hiccup

I am wondering what the new red ones are like I haven't seen anything on them yet.

regards John

[Chrissaf]

18v seems a little high I use nominally 16V with a CDU to operate mine which seems to be the normal recommended accessory feed and extra for analogue which I use there are exceptions I know.

 

I assume you mean 16 volts AC. If so, that equates to a DC voltage higher than 18 volts DC.

 

All sinusoidal AC voltages are stated by normal convention as RMS values.

 

Based upon "Physics O Level" science. The PEAK AC voltage of a 16 volt AC RMS voltage is 16 x 1.414 = 22.6 volts. [1.414 is the RMS to PEAK conversion factor].

 

Once this 22.6 volt 'PEAK' AC voltage is full wave rectified you get an equivalent DC voltage of 21.4 volts [bridge rectifier drops 1.2 volts] if large smoothing capacitors are used OR a voltage nearer 19 to 20 volts if not smoothed. Either way, these are higher than 18 volts DC. Remember that a CDU outputs a DC voltage thus the input AC voltage is rectified within the CDU [typically, but not always, by half way rectification and not full wave which delivers even more power].

 

PS

PL-10s are still readily available, the question was about the PL-10W and PL10-WE which are different PECO products. PL-10s have 'Black' coils. The PL-10W variants have 'Green' coils to denote their 'Low Energy' green credentials.

 

[ColinB]

I think is is 18 volts as it comes off a 15 volt transformer, but I cannot guarantee that, it should be 21 volts, according to your formula, originally all the points ran off the raw 15 volts. I built the controller about 30+ years ago, I will measure it next time. It uses 15 volts as the op amps that I used for the rest of the circuits run on +- 15 volts, we are talking 1980's technology. I did some surfing and checked in my electrical engineering books and it should work, but obviously it doesn't. In all the formulee I found it appears it revolves round (Number of turns * current)  all squared, so if you double the number of turns you halve the current, so it should be same. As I said I am no expert, definitely not on AC and inductors, so I am obviously missing something, but there again so did Peco. Either way it doesn't matter, practically they don't work. I intend using a 16 channel accessory module that uses 5 volt switching, so I have got to use relays anyway, plus it gives me the option of digital and analogue control, so I will just use them where I am not loading them up with microswitches.

[Chrissaf]

In bandying about all these voltages ... 15 volts this ... 18 volts that ... it is essential to state whether these voltages are AC or DC.

 

AC and DC voltages are not the same in the way that they are used in electrical calculations. And therefore their numerical values can not be interchanged as representing the same measurement of voltage. As I said in my last reply, sinusoidal AC voltages are stated as RMS values. You have to understand what RMS means. It is a mathematical way of expressing equivalent power in an AC waveform.

 

Then there is 'off load' and 'on load' stated voltages. Most AC transformer voltages are stated 'on load' at their rated current load. So a 15 volt AC transformer will easily measure 18 to 21 volts AC when 'off load', but it is still labelled as a 15 volt AC transformer.

 

.....it should be 21 volts, according to your formula.

 

Not correct.

 

The 21 volt figure was quoting the DC Voltage after DC rectification, whereas the 16 volt figure was an AC RMS value ..... something completely different.

 

A 16 volt AC RMS voltage is a 'PEAK' AC voltage of 22.6 volts, but any normal AC multimeter is calibrated to read the RMS value ... in this case 16 volts AC.

 

This is the very 'Ping Pong' 'To and Fro' 'Going round in Circles' dialogue I was trying to avoid by not commenting on the original question earlier. And I now wish I hadn't bothered.

[ColinB]

It is very nice you explaining it to me and I may be a bit flippant about voltages, but I know exactly what you mean, the information about the tests on solenoids filled in the gaps. I did power and machines for three years, it was part of my 4 year electronics degree. So yes I know exactly what RMS is, I know about ripple and maximum values, I also know all about power supplies, I used to design them. It is just I didn't want to say anything, especially after last time's telling off. I know very little about inductors and solenoids because basically they don't really follow ohms law and I have never really used them, same with triacs and scrs, other than for crowbar protection in power supplies. The only thing I do know about solenoids and inductors is to put a reverse diode across them to stop the back emf killing the driver. Normally I would go and ask a colleague at work, but I retired. So yes I know the difference between AC, DC, half wave rectified AC etc, I may be a bit rusty but when it comes to the crunch I know what they are and I still have a ton of books on it. As for the 18 volts I need to check my power supply, as I said I initially designed the box as a 4 track pwm controller, it has been modified extensively over the years plus I have bought in cdu, so I have not analysed what voltage it runs at.  I think the cdu required 15 volts AC as an input so that is exactly what it got as for its output, I must at some time measured it and got 18 volts, but for all I know it could have been the multimeter reading some transient. If it was important, I would measure it properly.

[96RAF]

OK - that is great theory, which I fully understand, but in practice this is what I have seen in recent testing.

 

The new HM6010 DC Point and Accessory Module (PAC) module is the R8247 Point and Accessory Decoder (PAD) of the DC world, except it has themsame number of capacitors but they are half the value of the DCC module and we know the R8247 is no muscle mechanic when it comes to throwing solenoids, especially in pairs.

 

The basic HM6010 module design is almost the same as the R8247 apart from the HM6010 having blue tooth connectivity to the operating app rather than being hard wired to a controller and it also has a high amp output on one port to be able to drive a turntable motor.

 

The PAC unusually has two alternative modes of power - 15vDC i.e the same as Select and Elite or eLink or direct DCC track voltage as output by any of those DCC controllers. One would think the internal circuitry of the PAC would produce the same potential at the port outputs, but ...

 

... throwing points - on straight DC voltage the HM6010 is not that reliable, especially throwing paired solenoids, but power it from a DCC track voltage and there is a noticeable increase in throw potential. You can actually hear the difference in click between the two powering arrangements on this module, which is factory set at the default 100mS pulse. Work goes on to try various pulse durations on the HM6010 as is currently possible to set on the R8247 via CVs.

 

Given that the CDU output of these modules is governed by the capacitor value and quantity then one would expect the R8247 PAD to out perform the HM6010 PAC by a wide margin.

 

Now if we look at the new basic DC controller R7227, which has the same value capacitors as the PAC but only two rather than four, yet it will reliably throw a pair of solenoids on a standard 15vDC power input.

 

Open to further discussion.