[bobleecnc]

Hi would anybody have anyold vexta catalogs theyed like to share info from ?
I'm looking for the holding torque inparticular for some old vexta ph299-01 steppers both bipolar and unipolar if anybody has them the rest of the data would be nice too but I'd really like to know what their torque ratings are.
Thanks Bob

[Al_The_Man]

3VDC 4A/Phase 306oz/in holding T.
Al.

[bobleecnc]

Thanks Al would that be bipolar or unipolar and is there a formula for figuring this out Ive got some other old motors with just the voltage and amperage ?
Bob

[Al_The_Man]

Unipolar 2 phase 1.8°
Al.

[dertsap]

ph299-01 ive been running a couple of ph299-01 unipolar and they are strong motors , i beleave that rating will be unipolar from what ive gathered (which isnt much)
they are great motors

[bobleecnc]

Thanks guys for the help .whats the difference between steppers and servos? can a stepper be used on a servo board ? is it just a matter of including an encoder for closed loop ?

[vacpress]

bobleecnc.

steppers and servos differ greatly in operation.

most servos are much like a standard motor. 2 wires, polarity controls voltage, an encoder and special electronics take care of closed loop positioning. man

in steppers, a number of coils are excited in a specific pattern, causing the armature to rotate preset amounts (usually 1.8 degrees). the drivers rapidly fire this sequence to 4 or more wires. the positioning is open loop, usualy. this means accuracy is maintained through overall electrical and mechanical robustness. for this reason it is probably best to over-compensate when doing a stepper design.

for more information, please, checkout wikipedia or some other soure of information. there is huge books of information regarding the types and control of the various motion-control motor actuators, and still more thick books describing their differences.

in general, steppers will cost less, servos, in general, provide a more reliable, robust, and accurate system.. a properly designed stepper system will outperform an improperly designed servo system.. and vice versa.

HOWEVER, I have worked with 15,000 to 20,000 router tables using open loop steppers.. this was fine, and the machine was very accurate and reliable. i am certain servos in the same application would have been only an incremental improvement, and for many tasks(all?) would not have produced any benefit....

other people where will have more information

[bobleecnc]

Thats a pretty good explanation thanks alot for the help
Bob

[bobleecnc]

dertsap what controller software are you using to run your ph299's?

[dertsap]

mach 2 and kcam with a stepper world fet3 board @ 24v ,3/4-6 leadscrew, if your looking to buy any other motors avoid the ph299-02 motors they are 6v 2amp , they are strong but way slower ,i have one for the z axis with 1/2-13 screw ,i had nema24 118oz motors at the same voltage and amperage ,that could out perform those motors except at very low speeds the ph299 has way more torque

[bobleecnc]

thats great I am using mach3 can you tell me how you set up your 299 motors in mach
I'm using a 5/8-8 screw would the steps per rev be 1600?
what about the velocity and acceleration settings can you give me a ballpark setting for these motors something to get me started my motors are ph299-01 and I think that I'm going to change to a bipolar board do you like your stepper world board how many amps can it handle? sorry to pick your brain but I could use all the help you can give and will really appreciate it
Bob

[bobleecnc]

Hi Dertsap I was over to stepper world looking at the fet4 withthe mosfets upgrade looks like just the ticket dou you need there software to run your steppers of it? or can you just use Mach? another question are you using an acme screw and what kind of nut? mine is an acme with a m6 nylon nut with a 1" long thread do you think the thread length is too long?

[dertsap]

mach works , if you can afford to buy a chopper driver , the problem i find with the fet is constantly changing the power resistors when i want to try a different voltage or motor , there is a unipolar chopper driver on ebay that is rated for 6 amp for 159 bucks for 3 axis , the problem with the high amp motors is the more popular favourites can t run them except gecko , after months of aggonizing myself ,i just ordered the gecko drives , if its a hobby that your going to carry for a long time then i would advise spending the bit more , i always learn the hardway and am buying the same thing twice
but with that being said the fet boards do work quite well , you can push them to 8amp 50v ,so as far as a cheap board goes they are good ,
but not as efficient as the chopper driver