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  1. #101
    Personally, I wouldn't bother with the resistor at all. Seems like unnecessary complication, given three or four drivers draining the caps on power-off. Main use would be draining the caps during testing with nothing else connected, but that's a bit artificial anyway. Heating was why I suggested the value I did, which would only be dissipating a watt or so, but why bother?

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  3. #102
    Quote Originally Posted by Neale View Post
    Heating was why I suggested the value I did, which would only be dissipating a watt or so, but why bother?
    Depends on how the control is wired.!
    One reason to bother is that when a drive faults or E-stop occurs the motors will continue to rotate for fraction of second until power is drained. No big deal you'd think.!! . . BUT. . it is a big deal with Slaved motors if one drive faults and other doesn't because the one that doesn't fault remains under power until power is drained. The faulted drive removes power and stops rotating so the gantry gets racked every time.

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  5. #103
    Quote Originally Posted by JAZZCNC View Post
    Depends on how the control is wired.!
    One reason to bother is that when a drive faults or E-stop occurs the motors will continue to rotate for fraction of second until power is drained. No big deal you'd think.!! . . BUT. . it is a big deal with Slaved motors if one drive faults and other doesn't because the one that doesn't fault remains under power until power is drained. The faulted drive removes power and stops rotating so the gantry gets racked every time.
    Unless you have the driver fault relays and enable signals integrated into the design, then they all stop together or as close together as possible.
    Spelling mistakes are not intentional, I only seem to see them some time after I've posted

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  7. #104
    PAULRO's Avatar
    Lives in LIMERICK, Ireland. Last Activity: 4 Weeks Ago Has been a member for 4-5 years. Has a total post count of 178. Received thanks 2 times, giving thanks to others 198 times.
    Initially i was not going to use a resistor because of the drivers draining as pointed out. i've read a lot of posts that discuss this and i know a lot of the experienced`builders don't bother because of the reasons stated. but i will be using a relay in the e/stop circuit anyway and it will have an empty N/C contact available so it's an extra terminal for the resistor and an extra piece of cable to hook it in. i think that's all that's required anyway? if i don't use it i will definitely integrate the fault relays and enable signals as Eddy suggested. on another note my toroidal coil arrived friday. i should have the cap and bridge this week, hopefully. the coil has 3 windings http://www.airlinktransformers.com/c...nge/CM0625225/ the colours are as follows: coil 1 BROWN / BLUE 1.6 ohms
    coil 2 BLACK / RED 0.5 ohms
    coil 3 YELLOW / ORANGE 0.5 ohms
    so i assume from this that the following
    Coil 1 = mains supply 230 vac
    coil 2 = 25vac
    coil 3 = 25vac
    and if i join BLACK and YELLOW together power up and meter across RED and ORANGE i should get 50 vac OR 0 vac . a change of the secondary coil arrangement if i read 0 volts. i will try it tomorrow to see.

  8. #105
    Recently bought one of the Airlink trafo's. Join black/yellow together and red/orange will give you 50v AC or there about.

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  10. #106
    Quote Originally Posted by EddyCurrent View Post
    Unless you have the driver fault relays and enable signals integrated into the design, then they all stop together or as close together as possible.
    Yes and exactly why I said depends on how control is wired.!! . . . Several why's to do same thing. Fact still remains that it's NOT ok if control NOT wired in correct Manner.!

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  12. #107
    PAULRO's Avatar
    Lives in LIMERICK, Ireland. Last Activity: 4 Weeks Ago Has been a member for 4-5 years. Has a total post count of 178. Received thanks 2 times, giving thanks to others 198 times.
    i'll have to give that a go. above all the system has to be safe and i would like to use the functionality of what the boards have to offer . the notion of draining the caps as quickly as possible is still worth a shot too because if i have to go into a cabinet with caps holding a charge then i rather go in when they're safe. i'll probably put a cover over the psu to be on the safe side. either way at least the conversations on the blogs really bring it home about the safety and choices available.

  13. #108
    PAULRO's Avatar
    Lives in LIMERICK, Ireland. Last Activity: 4 Weeks Ago Has been a member for 4-5 years. Has a total post count of 178. Received thanks 2 times, giving thanks to others 198 times.
    i have 4 core 1.5mm sqrd. cy cable on order for the steppers, is there a recommended cable for the spindle?http://2.2KW WATER COOLED SPINDLE MO... OWNING | eBay.

  14. #109
    Quote Originally Posted by PAULRO View Post
    i have 4 core 1.5mm sqrd. cy cable on order for the steppers, is there a recommended cable for the spindle?http://2.2KW WATER COOLED SPINDLE MO... OWNING | eBay.
    Same cable will work if you have ordered enough. Either don't use one of the cores or use the 4th core for an earth if you want. Personaly I don't bother with earth on spindle and just don't use 4th core.

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  16. #110
    While the cable you have would work, and many people use that I'm sure, if you look in the manuals for 2.2kw drives you will see that 2.5mm^2 is generally recommended.
    Also I think it's a good idea to take an earth directly to the spindle because if you have a motor to earth fault a lot of current will flow, if you don't have an earth wire it could flow though the bearings finding a path to earth and this could ruin them. If you were selling these things commercially they would have to meet regulations which most likely also encompass manufacturers recommendations, but if it's for yoursefl then you have to decide how far you want to go.
    Spelling mistakes are not intentional, I only seem to see them some time after I've posted

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