motor size

[psycho_fling]

Hi Guys

Does anyone know if the graupner speed 900 bb turbo motor aka speed 900 motor has changed in size?

i bought one and it arrived today, i'm sure my others at home are much bigger and beefier i've checked all the measurements to the site and the check out so i haven't got a different one to the one i ordered as far as i can see

anyone with an 'old used' one that they don't mind telling me the dimensions off that would be helpful

cheers guys alex

[leorcc]

Re: motor size

The last ones we bought about 6 months ago are still exactly the same size as the ones we bought 5 years ago.

[razerdave]

Re: motor size

I've just compared my new motor and old motor after getting a new gear today, and I concure with Alex:



Having inspected it, it looks like there is no internal capacitors on the new one

[RogueTwoRobots]

Re: motor size

Wow, that is a bit smaller now. Hope the performance isn't compromised as a result, although it would make it easier to fit one into Drumroll II. What shop did you get that from Dave?

[razerdave]

Re: motor size

Westbourne models

[robotic_ants]

Re: motor size

The site just calls it a 900 BB Turbo 12v and does not make any mention of the brand being Graupner or it being part of Graupners speed series of motors. While the specification matches it has no Graupner sticker or face mount in the picture. Did your's come with a sticker and a face mount? they are also usually boxed.

Integral suppressors are one of the main selling points of the motor, you say the one you received doesn't have them but the site clearly say's Special high-performance motors with integral suppressors. I'm wondering if its a replacement or copy motor, because it is very hard to find new Speed 900's especially for the price they sell the motor for.

They could get away with it if the motor is 900 class in size. That it has ball bearings supporting the shaft. Turbo can be a fairly generic term not really describing the motors performance as you could call any speed turbo. As for 12v-24v this would be the average voltage of a 900 class motor. Unless it comes with the Graupner branding, box and face plate i'd say its a alternative motor.

[robotic_ants]

Re: motor size

I've done some digging and found this motor which appears to be the one Westbourne models is selling....

900 Torque Motor
900 High Torque motor from Caldercraft Electric Motors (CEM).

Nominal Voltage: 12V
Operating Range: 6-24V
RPM at Nominal Voltage: 3000
No Load Current: 0.4A
Current at Nominal Voltage: 5.0A
Stall Current: 20.3A
1/4in plain output shaft

http://www.model-dockyard.com/acatal...ve_Motors.html at the bottom of the page.
http://www.jotika-ltd.com/Pages/1024...gs/CEM900T.htm
http://www.cornwallmodelboats.co.uk/...og/cem900.html

The picture is the same as the motor on the Westbourne models site. Lets compare the stats..

Graupner nominal voltage = 12v
Caldercraft nominal voltage = 12v

Graupner operating range = 6-40v
Caldercraft operating range = 6-24V

Graupner no-load speed = 6500rpm
Caldercraft no-load speed = 3000rpm

Graupner no load current = 1.1A
Caldercraft no load current = 0.4A

Graupner current drain at max efficiency = 8.0A
Caldercraft current at max efficiency = 5.0A

Graupner stall current = 54A
Caldercraft stall current = 20.3A

The Caldercraft motor will not perform anywhere close to what the Graupner 900 series motor will produce. The biggest areas being the no load speed, lower operating range and lower stall current with indicates a poorer quality of motor. It is very deceiving for Westbourne models to sell this motor and not update the specification.

But the major insult I think is the price difference Model-Dockyard sells the Caldercraft 900 motor for £26.40, Cornwall Model Boats sells it for £25.85 but Westbourne models still charge a premium £31.97 a big £5 difference.

Well that's all I have left to say really, I should be a detective

[psycho_fling]

Re: motor size

yes i knew i was right

yeh i did wonder as there were no stickers or box at all

i think i gonna be returning mine as i need the real thing

cheers all

[psycho_fling]

Re: motor size

i also got mine from westbourne models like Dave

when you search the exact motor name in google it somes up with the same name on the westbourne model site however from then on there is no mention of the graupner name

also copied the specs from westbourne site

Specs
Nominal voltage 12 V Operating voltage range 6 ... 40 V No-load rpm 6500 min
No-load current drain 1,1 A Current drain at max. efficiency 8 A Current drain when stalled 54 A
Length of case, excl. shaft 85 mm Shaft diameter 6 mm Weight 645 g

which i believe lines up with the real graupner version?????

when i got it and thought it looked small i weighed it and it is roughly 500g not the 645g they say


hmmmmmm very annoying to say the least.......

[RogueTwoRobots]

Re: motor size

Many thanks for that info Chris, excellent detective work
I suppose the lack of sticker/box should have been a pretty obvious give-away but it certainly didn't cross my mind.

When I got my Speed 900s they were £27 from Redbank Models and for a while they were the cheapest I could find. They've now gone up to £37 on there, but considering that's only £6 more than buying the Caldercraft motor from Westbourne, I think it's a small sacrifice for a much better performance.

The Redbank Models link for anyone looking for the Graupner motor: http://redbankmodels.co.uk/product_info ... cts_id=759

[robotic_ants]

Re: motor size

Westbourne models should not really list the motor as 900 BB Turbo 12v they are the only supplier to do this, every other site just lists it as a 900 Torque Motor which I think makes it fairly clear that it is a different motor. The deceiving bit is BB Turbo 12v as you only find this on Graupner motors. That combined with the incorrect description is extremely misleading, and I can imagine at that bargain price for what people might think is a Graupner they have sold quite a few.

I would rightly send it back if it's not what you expected and let them know why. If they are decent people then hopefully they should correct the site soon so no one else is mislead.

[razerdave]

Re: motor size

Thanks for all the info boys. I'm going to be getting a pair as spares at some point, but to get me ready as soon as, I'm getting a speed 900 from Tom Armitage to use. I'm not going to return the Fake 900 because I think it may be a viable weapon motor for my future kilobot

[RogueTwoRobots]

Re: motor size

I think it may be a viable weapon motor for my future kilobot

:shock:
What have you got planned for a kilobot?! Considering that motor takes up almost 40% of the weight limit, you aren't going to have much left for, well, everything else.

[razerdave]

Re: motor size

You forget Jamie. I'm an antweight builder, and if there is stuff I can do, its build small. You wait and see

[RogueTwoRobots]

Re: motor size

I shall indeed wait and see, as you've got me intrigued now :P