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[pugwash]

As a total electrical novice could someone explain what they are compared to
other electric motors and why they are so expense - are they worth buying
for a normal scale speed model

Pugwash

[hopeitfloats]

have a look at this page.  http://www.model-dockyard.com/acatalog/Geared_Drive_Motors.html#aCEM550G    i dont know why they are so expensive but like most model related items i think the manufacturers think of a price then treble it

[Shipmate60]

Overpriced, electrically dirty and noisy, a 550 on a 3:1 gearbox does then same job at half the price.
But some still swear by them, others swear at them.
They were superb motors during the 1960's/70's, but have been superceded several times in modern times.
The only reason they are used in large warships is the noise they produce can be roughly described as sounding like a gas turbine under load.
As you might have guessed I am not a fan of these motors at all.

Bob

[FullLeatherJacket]

like most model related items i think the manufacturers think of a price then treble it

Oi, referee!! Red Card that man!!
I'd agree entirely with Bob's verdict on these motors, but there are still folk who pay silly money to obtain them. Takes all sorts, I guess.
FLJ

[hopeitfloats]

LOL when i was writing  i thought i hope FLJ doesnt read this. please forgive me . FLJ is the rare exception to selling overpriced model items.

[pugwash]

Thanks for all your replies gentlemen - I know I have'nt got to bother saving up to buy one,
but I still dont know what they are, except they come fitted with a gearbox.

Pugwash

[Shipmate60]

They are a large (for models) DC motor made in Germany.
Over the years they have a good reputation for reliability but I have had several plastic pinions in the gearbox fail.

Bob

[pugwash]

They are a large (for models) DC motor made in Germany.
Over the years they have a good reputation for reliability but I have had several plastic pinions in the gearbox fail.

Bob

Thanks -  Pugwash

[Perkasaman2]

Hi Pugwash, They were made by 'Marx' in Germany and were excellent for spinning a very large coarse pitch propeller ........ tugs etc. They were light, largely trouble free 'fit and forget' motors with integral gearboxs. They were modular, easily mounted and their output shaft is sited low which is ideal for large models with a horizontal propshaft presenting/aligned close to the keel. I believe they were also advertised as 'Meccano' friendly. At the time they solved specific problems/answered needs, but at a premium price  . (Incidentally their main motor shaft was extended at the other end to also enable direct drive 1:1 simultaneously or as an alternative to the geared output shaft. They may be electrically dirty, however, they draw low amps, can work very hard  and run for a very long time in large models using  large inexpensive sealed lead acid batteries. 

 Here's a pic of both sizes, alongside other motors:

[pugwash]

Perkasaman,  Thanks for your reply - I'll forget all about them and buy a more reasonably
priced motor and put the money saved towards a new kit

Geoff

[FullLeatherJacket]

Pugwash
If you post the name of the kit or plan you are building then I'm pretty damn sure the assembled masses can come up with a suggestion (or twelve) about what motor might best suit.
FLJ

[Canopus]

As an alternative to these large and expensive motors you may want to try a car scrap yard and get a blower motor from behind the dash board. My favourit comes from an old Talbot Horizon - dead easy to get out and superb runners. They are of a similar size and are 12 pole and run really quiet with loads of torque. I run two in a 6 foot battleship on 6 volts wired in parallel and they draw 3.5 amps on full speed.

Last time I bought one of these was several years ago but it cost me £5.

Hope this helps

G

[snowwolflair]

Monoperms, Decaperms, Hectoperms were the BMW/Merc of the motor world in the 1970/80s.

They are motors that if run in properly, still cannot be beaten for reliability - truly fit and forget.

too many have been "raced" and the comutator scarred and windings burned - these are the ones who get criticised.

Personally I buy old ones and refurbish them so I generally can get a good motor for £15-20.  Once rebuilt I run them at half speed for six hours in both directions from a battery, or a digital train controller, never an old rectified power supply.  The result is a very smooth motor.

Some of the new motors nowadays are as good or better, its all a question of preference, run badly new motors are just as problematic.

Personally for fast (not scale) I use brushless.