Servo question

[scrambled]

I finally have saved up some money, so now i can replace the electronics on my MHP mill

The problem is that I can only read the id plate on the Z axis motor.

The id plate reads

TTB2-29360-1210-BA

cont `6.1 amps
peak 90 amps

LB - FT 6.5
peak 26.3

max speed 2000 rpms
Tach 19

it also has a brake that reads

volts 90
amps .28
LB FT 6


I have tried several online conversions to convert FT LB to watts, and it seams low
Any one have a idea what this is in WATTS?

next question.

If the servo amps are the same, should the x and y axis be close to the same size servo motor?

Since the Z axis has a brake (also a large counter weight) would the X and Y axis need a brake also?



thanks for the info



Steve

[hub]

Originally Posted by scrambled I finally have saved up some money, so now i can replace the electronics on my MHP mill The problem is that I can only read the id plate on the Z axis motor. The id plate reads TTB2-29360-1210-BA cont `6.1 amps peak 90 amps LB - FT 6.5 peak 26.3 max speed 2000 rpms Tach 19 it also has a brake that reads volts 90 amps .28 LB FT 6 I have tried several online conversions to convert FT LB to watts, and it seams low Any one have a idea what this is in WATTS? next question. If the servo amps are the same, should the x and y axis be close to the same size servo motor? Since the Z axis has a brake (also a large counter weight) would the X and Y axis need a brake also? thanks for the info Steve

- Instead of converting torque to Watts, I would try to find out the Voltage of the motor and then just muliply it with the Amps to calculate the Watts.

- I have no idea of motor size for your X & Y. You need to estimate motor size by knowing mass to be moved, ballscrew pitch, cutting forces, wanted acceleration etc etc

- I don't think a brake would be required for X & Y.

Hub

[mike_Kilroy]

only an axis that can fall often has brake so no on x,y

watts is nice but to get right drive buy one rated for the 6 amp current continuous and 120vdc output the motor is rated. forget watts.

ps: 90vdc brake on my motor is arrived at by a 120vac thru a 10 amp $ 1.00 full wave bridge rectifier module.

if u want the motor part nos for x&y that u cannot read nameplate on, list my drive part nos - we imbedded the motor part no into the drive part no most of the time....

[mike_Kilroy]

ok on pm rcvd.

watts are:

hp=N8T/5252=6*2000/5252=2.2hp

2.2hp*746w/hp = 1700 watts. yes, these are significant motors.

[scrambled]

Thanks Mike- Those motors are larger than i had hoped for , but atleast i have a starting point.

I can't afford to buy new servos that are that size until i can start to use the mill more. Is it possible to buy new or used kollmorgan drives and reuse the existing servo motors?


Thanks again

Steve

[mike_Kilroy]

Hi, We looked and the only used kollmorgen drives we could supply are way too expensive for this (prob in excess of $1500 ea), but AMC or servo dynamics or one of the other folks who advertise on here is prob your best bet; you just need 6amp continuous, 120-150vdc bus drives with the input type of your choice (+/-10v speed command?) that accept tach feedback, or ignore the tach and use the encoder to the control and set drives in current mode....

[Al_The_Man]

If going step/dir maybe Larken Viper drives would do it?
Al.

[scrambled]

Thanks Mike and Al the Man-

I was not sure what to do with the tach wires. But if i understand correctly, i just ignore them and dont connect them.

Sounds easy enough. I have both, an extra viper 200 and granite devices xe 160

I am planning on using the dspmc from vital systems and i think it can use either step/ direction or +-10 volts


Steve

[Al_The_Man]

I usually remove the tach brushes when using the Torque mode to avoid any mechanical complications.
Al.

[hub]

Originally Posted by scrambled Thanks Mike and Al the Man- I was not sure what to do with the tach wires. But if i understand correctly, i just ignore them and dont connect them. Sounds easy enough. I have both, an extra viper 200 and granite devices xe 160 I am planning on using the dspmc from vital systems and i think it can use either step/ direction or +-10 volts Steve

It won't work that way. You need to connect an encoder instead of the tach..

Hub

[scrambled]

Hub

My motors have both a tach and encoders. That is what was confusing me. Not to sure what the purpose of the tach is.

My mill also has an option to mount the encoders one either /or both the ball screw or servo motor

Is either better than the other?


Steve

[Al_The_Man]

The tach is used with a drive that has velocity mode.
Usually now the drive is set for Torque mode so the tach is not required.
The encoder can go on the end of the B.S. or motor.
Al.