Is this a really good stepper?

[Robin Hewitt]

I'm getting a bit behind the times with the technology, is this a really nice stepper or could I do better? Find it cheaper?

http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=320353807657

My problem is nobody tells you about the motors they are trying to sell you anymore. The spec is something like "2Nm" and that's it, finis, like why should you need to know more than that? Isn't 2Nm so amazing you can't wait to hand over fist fulls of your hard earned?

At least this bod tells you half torque at 1500rpm. Okay that probably means driving it at 80 volts, but at least you know it doesn't wash out before you can get any appreciable speed out of it, plus you can upgrade you drivers later to get amazing performance.

Confused of Seaford :confused:

[cocoa_cnc]

That looks just like the FL86STH65 that im sure works out cheaper from MCP or Zapp. I have one of the CNC kits from MCP and am very happy with the drivers and motors -but am yet to have it driving the machine so im not sure how well they perform under load.

I have 4.5Nm for X&Y, 12Nm for Z (and hoping i got the selection right)

hope this helps

[Robin Hewitt]

MCP and Zapp do sell similar hybrids but they tell you diddly squat about them beyond the holding torque and outside dimensions.

If this is a FL86STH65 then MCP sell a different winding variant that can only handle half the current. They have a FL86STH80-4208 which looks interesting but they don't even give you a price for that one, web searching the part number finds lots of info in Russian. I don't do Russian.

The torque against speed graphs for the hybrids seem to tail off rather than plummet which quite refreshing, but buying a stepper without seeing any graphs at all does seem a bit like buying a pig in poke.

I was looking at a 2.8Nm motor, sounded good, but that was holding torque, reading a bit further I found a "detente" torque of 0.1Nm, do they mean pull in torque? Hardly whoopy doo.

[Robin Hewitt]

Progress, it's made by the Changzhou Fulling Motor Company

http://www.alibaba.com/product-gs/51...r_Square_.html

But I obviously misunderstand detente torque :confused:

[John S]

The Chinese aren't very good at Detente, you need the French for that......

John S.

[cocoa_cnc]

Isn't the detent torque the deviation from the holding between phases?

[Gary]

I doubt that motor will give half the holding torque while running at 1500 RPM, and saying max speed is 3000 RPM, is very misleading.
Torque curves are available, and all you need to do is ask.
We don’t put the curves on the site, because it causes confusion.
A torque curve is very specific to the actual driver, actual Voltage and resolution, and will vary greatly with different drivers, voltage and resolution.
The comment about the Chinese are not good at detent torque and the French are better, is laughable when you consider that 99% of stepper motors are made in China, and out of the 1% made elsewhere only 1% of those are made in France, and they have laminations Stamped in China :)

[John S]

The comment about the Chinese are not good at detent torque and the French are better, is laughable when you consider that 99% of stepper motors are made in China, and out of the 1% made elsewhere only 1% of those are made in France, and they have laminations Stamped in China :)

Note the spelling ;)
I know it was late when I posted but I thought the Brits might get the pun.

John S.

[Robin Hewitt]

I know it was late when I posted but I thought the Brits might get the pun.

Don't worry John, engineers know what a "detent" is but I needed my dictionary for "detente", the easing of strained relationships

I think Gary is feeling squeezed, hardly my intention. It looks like the Changzhou Fulling Motor Company have the cnc market fairly well stitched up when it comes to 2 phase NEMA 34 steppers. Unfortunately this new breed of CNC fanatics who buy stepper motors by holding torque rather than performance could eventually lead to the manufacture of some pretty weird motors if they ever become a significant part of the market rather than just a fringe. Let's hope it never happens :D

I can see Gary's problem, if he does the graphs showing the pull in torque falling away as speed increases when others don't, it's hardly going to help his sales. The market already seems hell bent on NEMA 23 size motors, possibly because you can fit it straight on the end of a ball screw on a table top mill without overhanging the bed.

However my colours are somewhat nailed to the mast, I have cut my fittings to take a NEMA 34 max length 90mm so it's either the FL86STH65 or the FL86STH80. The ebay item seems to have higher Ampage coils fitted than the UK offering, but do I actually need it? It certainly doesn't take a vast amount of torque to turn my handles, OTOH my max speed on a G00 is a tediously slow which is why the torque/speed graph is all important to me when deciding.

[John S]

Torque speed is pretty much useless as they often send the wrong graphs out anyway.
Some exporters are only clearing houses and will ship any documentation they can get there hands on, lets face it one 34 looks very much like another 34 .

John s.