Replacing Mashima motors

[Down_Under]

Hi all,

 

I've been trialling out these 

 

https://www.ebay.co.uk/itm/Japan-Mini-Micro-5-Pole-Electric-Big-Coreless-Motor-DC-3-7V-5V-6V-12V-High-Speed/193592365341?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D078579b7ca5d4a32b6e813e2d6d94605%26pid%3D100675%26rk%3D1%26rkt%3D15%26mehot%3Dpp%26sd%3D193592365341%26itm%3D193592365341%26pmt%3D1%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A7681270b-500b-11eb-a7e8-6ef2a71592fa|parentrq%3Ad747c1971760a68ba65ca17bffcbd636|iid%3A1

 

I bought models B, C and D.

 

Here is the C type fitted to a Judith Edge Janus chassis and a High Level Road Runner + (54:1). I had to sleeve the shaft from 1 to 1.5mm and in doing so ensured there is no for and aft movement. it will crawl long under normal DC, even at relatively low levels of reduction (for a shunter) - 20 sec for a full wheel rotation without stalling. They have surprising amount of torque and I'd say quite a nice 12/20 or 12/24 replacement. I'm yet to run up to the full 12v as that is far beyond what I need for a small shunter. Very responsive to minor current increase. cant stop them with fingers at 3v - and the model C has normal Mashima mounting screw holes. 

 

 

 

 

 

 

 

 

Will try some of the double shaft variety as they look similar 

 

https://www.ebay.co.uk/itm/10mm-Mini-Coreless-Motor-Dual-Shaft-DC-6V-9V-12V-High-Speed-RC-Rail-Train-Car/192513133362?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20200520130048%26meid%3D3b34a177d0dc4ad6ac713fd37c333ba6%26pid%3D100005%26rk%3D2%26rkt%3D12%26mehot%3Dsb%26sd%3D193592365341%26itm%3D192513133362%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv5PairwiseWebWithDarwoV3BBEV2b%26brand%3DUnbranded&_trksid=p2047675.c100005.m1851

 

Good luck!

 

James 

Edited January 6, 2021 by Down_Under

[Ruston]

How easily do the worms that they are supplied with come off?

[Down_Under]

1 hour ago, Ruston said:

How easily do the worms that they are supplied with come off?

I gripped the worm with some pliers with the shaft pressed against the table and with some force it dislodged,  I then stuck it it in a GW worm puller and pressed off the worm. The worm seemed pretty undamaged by this brutal approach. 

 

 

 

I'm going to take one apart as they seem to have a large (ish?)  bronze bush at one end - bigger than most coreless motors that ive seen. the B and D have Mashima spaced screw holes, but larger thread - not sure what. Th C are identical to Mashima in spacing and thread. Reasonable heavy suggests a good size iron core - certainly weigh 2 x Mitsumi 

 

Comparison: 

 

Top to Bottom

Mashima 12/24

Mashima 12/20

N20

Coreless 10/20

Mitsumi 15/20

Mabuchi 16/27 (sold as 3-9v received 4v)

 

 

 

Large front bush on par with Mashima

 

 

 

 

 

 

The B and C type have 1.5mm shaft, but they are really stubby and possibly not to much use - only 2.0 - but the one with the worm is 8.5mm in lengthmm p

 

 

Edited January 6, 2021 by Down_Under

[Ruston]

Thanks. I've taken a punt on one with the worm.

[polybear]

Any guesses as to whether or not these will be subject to any VAT & collection charges post-Brexit?  If so they start to become somewhat more expensive....

Thanks

[PenrithBeacon]

I've tried taking worms off motor shafts' in much the same manner as shown earlier and all I managed to do was to damage the thread of the worm. Excepting that is the incident when I completely wrote off the motor!

Gripping the worm with pliers didn't work out well. 

[The Fatadder]

With the "C" model, how did you go about sleeving it to accept the High Level worm?

 

Will get a couple ordered this evening to experiment with.

[cctransuk]

2 hours ago, The Fatadder said:

With the "C" model, how did you go about sleeving it to accept the High Level worm?

 

Will get a couple ordered this evening to experiment with.

 

I believe - though I am open to correction - that High Level worms are available in a choice of bore sizes.

 

Regards,

John Isherwood.

[Izzy]

Shame the slower running 12v rated ‘B’ has the shorter shaft. 

[Down_Under]

9 hours ago, PenrithBeacon said:

I've tried taking worms off motor shafts' in much the same manner as shown earlier and all I managed to do was to damage the thread of the worm. Excepting that is the incident when I completely wrote off the motor!

Gripping the worm with pliers didn't work out well. 

I used the pliers to shift it enough to get a proper puller in behind it, making sure that I didn’t simply try and pull it off and damage the motor. 

[Down_Under]

3 hours ago, Izzy said:

Shame the slower running 12v rated ‘B’ has the shorter shaft. 

Same, I’m thinking of sleeving to 2mm to extend the shaft. The high level boxes do come with extended shaft support so this is an option too

[Down_Under]

4 hours ago, cctransuk said:

 

I believe - though I am open to correction - that High Level worms are available in a choice of bore sizes.

 

Regards,

John Isherwood.

correct - I know they make 2mm and 1.5mm no sure on 1mm. 

[Down_Under]

6 hours ago, The Fatadder said:

With the "C" model, how did you go about sleeving it to accept the High Level worm?

 

Will get a couple ordered this evening to experiment with.

I had a hunt in my brass tube box and found the closest 1.5mm OD thin wall tube. I found in reality these varied from 1.62 to 1.48mm with internal varying from 0.8 to 1.1mm. 
 

I went as close as I could get and reamed the internal diameter back to 1mm. A touch of loctite secured the worm on the shaft as I could not quite get a interference fit 

[Michael Edge]

5 hours ago, Down_Under said:

correct - I know they make 2mm and 1.5mm no sure on 1mm. 

Chris can supply 1mm bore worms.

[polybear]

To remove the worm get a couple of steel plates (or even better, a single plate with a slot in it a fraction wider than the shaft diameter) and place these in the gap between the worm and the front motor bearing.  Open a vice just a little wider than the motor body and place the motor in the gap with the worm uppermost and the plates resting on the vice jaws.  Then use a punch (that must be smaller than the shaft diameter) on the end of the shaft to punch the motor downwards, out of the worm.  Have a safe way to catch the motor so that it doesn't fall....

HTH

[The Fatadder]

1 hour ago, Michael Edge said:

Chris can supply 1mm bore worms.

Thanks,  I think  I will get a couple of motors ordered and have a play on my next build.

[hayfield]

14 hours ago, The Fatadder said:

With the "C" model, how did you go about sleeving it to accept the High Level worm?

 

Will get a couple ordered this evening to experiment with.

 

No need as you can order worms with 1 mm holes

 

(opps had not read further down) I ordered a couple of C type yesterday

Edited January 7, 2021 by hayfield

[Barclay]

Very interested in these, but am I missing something? The 'C' Type appears to be 6v ?

[DavidLong]

19 hours ago, polybear said:

Any guesses as to whether or not these will be subject to any VAT & collection charges post-Brexit?  If so they start to become somewhat more expensive....

Thanks

These aren't coming from the EU. I've bought a number of motors from Chinese suppliers with no problem. They just drop through the letter box! There may be some consideration of the total value of the order but so far this doesn't seem to have applied.

Having read about some of the new rules concerning VAT with the EU I suspect it may be easier to buy from China than from Germany! It seems that suppliers have to register for VAT with HMRC, charge VAT to the customer and then claim it back from HMRC. There are already some tales of European suppliers declining orders from the UK as they don't want the hassle.

 

David

[polybear]

30 minutes ago, DavidLong said:

These aren't coming from the EU. I've bought a number of motors from Chinese suppliers with no problem. They just drop through the letter box! There may be some consideration of the total value of the order but so far this doesn't seem to have applied.

Having read about some of the new rules concerning VAT with the EU I suspect it may be easier to buy from China than from Germany! It seems that suppliers have to register for VAT with HMRC, charge VAT to the customer and then claim it back from HMRC. There are already some tales of European suppliers declining orders from the UK as they don't want the hassle.

 

David

 

Thanks David - I suspected that would be the case but with the wierd and strange ways that Brexit appears to be affecting such things I thought it prudent to ask.  I've also purchased many items from China, virtually all without any issues - any that have been encountered have resulted in very fast refund and/or partial refund.

[Down_Under]

4 hours ago, Barclay said:

Very interested in these, but am I missing something? The 'C' Type appears to be 6v ?

You haven’t missed anything, they are sold as 3-6v motors. I haven’t run one up to 12v yet, only briefly to 6v or so. In my experience I didn’t need to run them at full noise as it where for the shunter I used to trial it on. 1-3v was sufficient even at 54:1 reduction to be realistic.   
 

I’ve used inline resistors to drop the voltage in mini (6mm x 10mm for axle

hung units ) 3v - 6v cordless motors to make sure they don’t burn out. I’m not so familiar with diodes, but I understand they can be used to perform a simIlar function to drop voltage if needed. 
 

Coupled to a 50 to 80:1 gearbox in a shunter I’d doubt you’d ever exceed 6v 

 

J

 

edit - voltage was done under DC conditions only. Yet to play with these under DCC 

Edited January 7, 2021 by Down_Under

[Down_Under]

I’m happy to attempt a bench test of some sort to get some useful numbers/standardised data for comparing motors. Just what sort of bench test/haulage test is required?  Is there a standard? Easy to measure? 

[Michael Edge]

I've bought all sorts of motors advertised as 6v or anywhere up to 12v, all I do is connect them up and run them while watching the ammeter. My nominal 12v DC supply is actually about 14v anyway but the vast majority just run with barely a flicker on the ammeter. If they keep running and don't get too hot I assume they are OK, they are too cheap to worry much about. The only exception to this is the 15mm square 6 pole motor which appears to run very warm but with no detrimental effect (and not much on the ammeter either) I've ordered some of the coreless ones so I'll find out in due course.

[Jol Wilkinson]

 

 

 

 

22 hours ago, Down_Under said:

I’m happy to attempt a bench test of some sort to get some useful numbers/standardised data for comparing motors. Just what sort of bench test/haulage test is required?  Is there a standard? Easy to measure? 

 

The EMGS Manual includes test date for the "usual" 12v model motors produced over many years, including Mashima, Sagami and Portescap. 

 

This is typical of the summary of a motor test, which includes performance graphs, dimension drawings and a general review of the motor.

 

PERFORMANCE SUMMARY

Free-running at 12 V d.c. Speed 13,500 r.p.m.

Current 50 mA Typical Max. operating speed at 12 V 11,000 r.p.m. Torque at this speed 10.4 g cm

Power output 1.2 W Current 200 mA Max. power output 2.0 W developed at speed 6,500 r.p.m.

Recommended max. current 500 mA

Suggested gear ratio 30:1

 

I suggest the speed and current/wattage figures are the most useful in comparing motors, while a dimensional drawing, to include shaft diameter and length as well as fixing hole centres/size/thread are also important.

 

I have a Bench Power Supply with controls for voltage and current output as well as displays for these, which would be ideal for measuring motor performance. Measuring torque and speed is more difficult and while the former could be ignored, speed is more important. 

 

Whether or not it is worthwhile really depends on there being a regular supply of specific motors. Those previously available such as Mashima were specifically designed (or found suitable) for 4mm models. Those being sourced on Ebay, Ali-express, etc. are produced for other applications and while some are suitable for our needs, we have no guarantee of continued availability, specification, etc.

 

 

[Barclay]

On 07/01/2021 at 20:53, Michael Edge said:

I've bought all sorts of motors advertised as 6v or anywhere up to 12v, all I do is connect them up and run them while watching the ammeter. My nominal 12v DC supply is actually about 14v anyway but the vast majority just run with barely a flicker on the ammeter. If they keep running and don't get too hot I assume they are OK, they are too cheap to worry much about. The only exception to this is the 15mm square 6 pole motor which appears to run very warm but with no detrimental effect (and not much on the ammeter either) I've ordered some of the coreless ones so I'll find out in due course.

I've had some of these 15mm square 6 pole motors for a while but this is the first time I have used one in a loco. I too was concerned that they seem to run quite hot, but after some running this one seems to have settled down nicely. It's far too early to be able to comment on longevity but I can say they are very powerful - the loco this one is going into weighs 400g and it will still spin the wheels if obstructed on the track. It's also ludicrously slow revving compared to most of 'our' motors - this loco tops out at about 16mph flat out at 12 volts, and that's with simple 40:1 Romford gears.