You will need encoders, so you can either buy the ones with or buy the ones without if you already have encoders. Also no problem asking questions
Hood

ok thanks so much I will have a look, but before buying anything I will let you know to advise me more in order not to make mistakes... thanks again
Robhi

hello,

what is the encoder please? every servo motor has its own encoder or an ecoder works for all the motors?
Robhi

DC motors can use any encoder that is of a suitable type for the drives, normally it will be incremental encoders with ttl square wave output.

Hood

OK thanks hood...
now I would like to buy the following items, i would to tell if the will work togother please:-
1) KL- 7220 Specification: $189/pcs
Unregulated Power Supply 1440W, 72VDC/20A ,120VAC or
230VAC
 2) Gecko 340 for servo motors

3)  KL34-170-90 (NEMA 34) Dual Shaft, Front Shaft
1/2" Rear shaft 1/4" 850 oz-in Peak 90V, $139 Special
Sale:$129  Specification (Skewed Rotor Design,
Green is Ground, Red is +, Black is Common)

thanks in advance
Robhi

The thing I see that may be an issue is the motor has a peak current of 30Amps where as the Geckos have only 20Amps max. I am not 100% sure but I think it will be fine but your best bet would be to email Keling and ask them as then you would have some comeback if they did not work.
How many axis will you be using as possibly the power supply will be on the small side for 3 axis unless you had one for each axis.

Hood

i will use one power supply for the  axis...
do you think it will not work well?
Robhi

I think 1 supply for 1 axis would be fine, it may also be ok for 2 axis but I dont think it will work for 3 axis if you will be moving all 3 at the same time.

Hood

ok thanks a lot  so i have to buy 2 power supply...
thanks Hood
Robhi

Ask Keling to make sure but as the motors you are buying have a continuous current rating of 7.5 amps you would be over the 20 amps of the supply if running all three at their continuous current, if drawing peak current (during acceleration for example) then you would be well over the rating of the power supply.
Hood