# stopping time



## JT. (Jun 5, 2013)

got a VFC on my lathe but now i wonder what is  a good stopping time in seconds to not burn out the engine 
i  need it to stop  as quick as possible    without hurting the motor to mutch 
is the use of a condansator (like notised in the manuel ) a good idea 
i can get a bigger dan needed condesator is thise a problem 

so Q1 what is a usable stopping time  from let say 250 rpm to 0 ?
    Q2 is a condasator usefull  ?


----------



## Ray C (Jun 5, 2013)

Hi JT...

It might depend on your particular motor and equipment but for reference, my lathe has a 3 second start-up and shutdown. The VFD I have does not consider this to be "dynamic braking" and does not need resistors or capacitors. If you want to use the dynamic braking feature for "instant stop" or instantaneous forward-to-reverse operation, the VFD manual will tell you what components are needed. Use the components that the manual recommends.

Ray





JT. said:


> got a VFC on my lathe but now i wonder what is a good stopping time in seconds to not burn out the engine
> i need it to stop as quick as possible without hurting the motor to mutch
> is the use of a condansator (like notised in the manuel ) a good idea
> i can get a bigger dan needed condesator is thise a problem
> ...


----------



## Restorer (Jun 16, 2013)

Add a dynamic brake board to the variable drive for quicker stops.

How quickly it actually stops will depend on how fast things are turning and how much inertia has to be dissipated.

For an occasional FAST stop just switch into reverse momentarily!


----------



## JT. (Jun 17, 2013)

ordered a breaking resistor


----------



## dirkvdh87 (Jun 17, 2013)

Hi JT.

Which vfd do u use?
Most can do compound braking, combining frequency ramp down and dc injection braking.
If instant stop is not necessary but only quick slowdown, a resistor can be omitted. Of course
this is all in proportion to your load flywheel effect.

If your vfd settings are correct, it is impossible to damage your motor independent of the 
ramp-down time. When you brake the rail voltage (dc) will rise if it gets to a certain level, if the
resistor is activated, the vfd will connect the resistor, so rail voltage lowers.
If you dont use a resistor the vfd will just not be able to accomplish the ramp down time and will
brake as quick as possible (working at the max. Rail voltage)

Dirk


----------



## JT. (Jun 17, 2013)

http://www.ebay.co.uk/itm/New-Updat...al_Components_Supplies_ET&hash=item4610377460


----------



## dirkvdh87 (Jun 17, 2013)

Don't know about this vfd, but it would work as i discribed since it has dc braking on board. 
Search the datasheet for brake functions...


But rest assured, if you open the link you can see that you have  
"*3 YEAR FACTORY WATTANTY" *:LOL:


----------



## JT. (Jun 17, 2013)

you got a pm 



manuel 

http://www.jinlantrade.com/ebay/invertermanual.pdf ​ 
​


----------



## dirkvdh87 (Jun 17, 2013)

Ok, this vfd doesn't combine dc and rampdown braking, no problem so.

Just set parameter p026 to '0'  -->  ramp down braking enabled
                          p028 to '0.1' --> lower ramp down frequency
                          p015 to 'lets say 5s'  --> ramp down time

DC-braking will not be necessary in your application, so set p030 to '0'

when the application does not stop quick enough (more than 5s) and/or you get an rail over-voltage error,
then you need to use the resistor to temper the rail voltage.

I think there is no parameter to enable the resistor output, so you have to change nothing to use the resistor.

Good luck with it...

--Dirk--


----------



## AlanR (Mar 10, 2014)

dirkvdh87 said:


> Ok, this vfd doesn't combine dc and rampdown braking, no problem so.
> 
> Just set parameter p026 to '0'  -->  ramp down braking enabled
> p028 to '0.1' --> lower ramp down frequency
> ...


I'll reply even though this is an old post.

• It's an Huanyang VFD

• This VFD does combine dc and ramp down braking so p030 should not necessarily be set to '0', DC braking does allow a faster stop.

• The terminals for the resistor are normally jumped if there is no braking resistor, remove the jumper and add the resistor in its place.

I just received my resistor today so I've been experimenting, without the resistor fast stopping times results in over current faults. I want to do tapping with the machine so I want fast stops, with the resistor in place I can even do "instant" reverses, before I'd get VFD faults.


----------

