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spideremanako
10-09-2009, 04:49 AM
Do You know the purpose of AUTOTRANSFORMER on this circuit? Can u explain clearly?
Magoo
10-09-2009, 06:36 AM
Low voltage start on motor.
magoo
spideremanako
10-09-2009, 07:59 AM
thanks can u explain further how it works? why is there a need for low voltage start in the motor
Yuri B.
10-09-2009, 08:01 AM
Sort of a (cheap) soft-starter, or to enlighten transition from low speed to high and vice versa. Only from the shematics is not clear - how km2 can make in.
absrbrtek
11-09-2009, 02:40 AM
It is used to reduce the inrush amperage on startup of the motor.
chemi-cool
11-09-2009, 11:56 AM
http://en.wikipedia.org/wiki/Autotransformer
absrbrtek
11-09-2009, 01:28 PM
That is not the same as an autotransformer used in a starter setup. Here is something a little closer: http://ecmweb.com/mag/electric_reducedvoltage_starters_choosing/
goshen
11-09-2009, 03:34 PM
Do You know the purpose of AUTOTRANSFORMER on this circuit? Can u explain clearly?

hi this system is used on big motors instead of y delta in the old days .
it works very similar to a rvs starter 'which reduces the voltage to the motor on start up ,then increases by transition, it uses a big transformer with diffrent voltage outputs the designer calculates the percent of full voltage for a softer start and connectes accordingly .we have high voltage 3.3 kv autotrafo starters, they do a fairley good job and last forever.
today we use digital softstarters with no transition at all which eliminates the crossover peak totaly.:)
Sandro Baptista
11-09-2009, 03:45 PM
I don't understand how can ever the KM2 be energized. The KM2 auxiliar contact is in series with is own KM2 solenoid and there is no other contact in parallel with KM2...
shooter
12-09-2009, 08:46 AM
the schematic is not correct find a good one.
or if not find then give a email and i will send correct one.

the transformer is used to lower the starting amps as otherwise the motor will take 6 times the nominal current.
Peter_1
12-09-2009, 04:17 PM
the schematic is not correct find a good one.
or if not find then give a email and i will send correct one.

the transformer is used to lower the starting amps as otherwise the motor will take 6 times the nominal current.

I don't see any problem in the schematic Shooter
shooter
12-09-2009, 05:56 PM
peter please explain sandro how km2 will ever be on.
the drawing is looks nice but does not work.
goshen
12-09-2009, 06:33 PM
hi the diagram is wrong the contact in series to km2 should be km1!