I DID see there's "braking units" AND "braking resistors". I am unclear on what's inside a braking unit. I am sure it has a self-resetting breaker at least. But that is not even all that good to have- opening of the breaker would cause the VFD to go into an overvolt error state. You won't likely need it- a 50W resistor can handle 200W for probably like 30 sec. So tripping for overcurrent in 3 sec would be unnecessary.
I think it's a thermal breaker actually, on the resistor, rather than a current-based breaker. Which is ok, just prevents exceeding max temp. But you won't ever approach that if you size the wattage correctly. I was wondering if it somehow used a lower resistance than you would normally apply and PWM'ed itself when lower braking currents are required. But I don't see how it could work that way, the bus voltage I think is fixed. From what I gather, a braking resistor should be fine. The electronic braking units, I don't know what that adds. Danny On 3/13/2016 8:47 AM, Gene Heskett wrote: > On Sunday 13 March 2016 09:30:30 John Thornton wrote: > >> I just used the the one for by the drive. I "think" not all drives >> would use the same resistor. Just looking at the GS2 and there are 12 >> different braking resistors. >> > All of which are $435 a copy & still need some sort of an extra, external > controller. AD thinks we are growing our own money on a tree in the back > yard? > > I'll look at the controller I have first. I should be able to do it for > under a $100 Ben Franklin picture. > >> http://www.automationdirect.com/adc/Shopping/Catalog/Drives/GS2_%28115 >> _-z-_230_-z-_460_-z-_575_VAC_V-z-Hz_Control%29/GS2_Drive_Units_%28115_- >> z-_230_-z-_460_-z-_575_VAC%29/GS2-23P0 >> >> http://www.automationdirect.com/adc/Shopping/Catalog/Drives/AC_Drive_( >> VFD)_Spare_Parts_-a-_Accessories/GS_Braking_Options_(Braking_Units_-a-_ >> Resistors)/Braking_Options_(All_GS_Drives)/GS-23P0-BR >> >> JT >> >> On 3/13/2016 8:03 AM, Gene Heskett wrote: >>> On Sunday 13 March 2016 07:40:25 John Thornton wrote: >>>> On my GS-2 with the braking resistor I go from 1800 fwd to 1800 rev >>>> in 1 second. I have both acceleration and deceleration set to 1/2 >>>> second. >>>> >>>> JT >>> That would be considerably more usefull than the controllers default >>> of 30 seconds. Do you recall the specs of the resistor you used? >>> >>> Thanks John. >>> >>>> On 3/12/2016 10:12 PM, Gene Heskett wrote: >>>>> Greetings everybody; >>>>> >>>>> Given that I note the vfd's seem to have an adjustable >>>>> accelleration control, and that my couple of hours playing with it >>>>> from its own front panel, I am led at ask the question of just how >>>>> fast can one of these things be reversed from say 1000 rpm at the >>>>> motor spindle? >>>>> >>>>> I ask because my present setup, using the OEM PM DC motor which is >>>>> all gear drive to the spindle, one of Jons pwm servo amplifiers >>>>> and a 125 volt dc supply, reversals at the turn around depth of >>>>> this cycle of a peck tapping operation, with the spindle doing 300 >>>>> rpms, is a very small fraction of a second, far less than 30 >>>>> degrees of rotation. Based on its reversal performance at 2500 >>>>> rpms being a slim second, I am concerned that the vfd may not be >>>>> able to reverse so quickly, and will impact my use of G33.1 >>>>> because of the turnaround over shoots. On my lathe, with its >>>>> fragile drive train and a 5" chuck, this overshoot is between 2 >>>>> and 3 turns at 250 running rpms. Usable, but if I don't stop it >>>>> soon enough, the tap may bottom out and break. >>>>> >>>>> What has been the experience of others using smaller vfd's and >>>>> motors? >>>>> >>>>> Can you still do rigid tapping safely? >>>>> >>>>> Thanks all. >>>>> >>>>> Cheers, Gene Heskett >>>> ------------------------------------------------------------------- >>>> --- -------- Transform Data into Opportunity. >>>> Accelerate data analysis in your applications with >>>> Intel Data Analytics Acceleration Library. >>>> Click to learn more. >>>> http://pubads.g.doubleclick.net/gampad/clk?id=278785111&iu=/4140 >>>> _______________________________________________ >>>> Emc-users mailing list >>>> Emc-users@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>> Cheers, Gene Heskett >> ---------------------------------------------------------------------- >> -------- Transform Data into Opportunity. >> Accelerate data analysis in your applications with >> Intel Data Analytics Acceleration Library. >> Click to learn more. >> http://pubads.g.doubleclick.net/gampad/clk?id=278785111&iu=/4140 >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users > > Cheers, Gene Heskett ------------------------------------------------------------------------------ Transform Data into Opportunity. Accelerate data analysis in your applications with Intel Data Analytics Acceleration Library. Click to learn more. http://pubads.g.doubleclick.net/gampad/clk?id=278785111&iu=/4140 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
