# motor on vsd wont speed up in delta but works fine in star configeration



## devil0808 (Nov 18, 2014)

hi, i have a problem, obviously.
current config :
Siemens Micromaster 440 connected to 4kw motor
auxiliaries digital input1 pnp config to original contactor set to start/stop
0-10v analog setting on AI1 pot control on panel to speed up and down.

basically i run it threw gearbox then connected to monopump/stator pump.

so had motor connected it was originally star config,threw variator, but mechanical variator are old and a mission to repair and costly aswell.

i took out variator connected motor to gearbox and pump but wont startup, adjusted boost on ramp up to 100% of current rating but would not turn.
now connected motor alone in delta configuration and i cant get why it wont speed up.
what it does is (starting at 0hz) turn pot up and it starts to run fine but only about 10% of its speed even when hz set to 50 it is still spinning at slow speed, and seems to have jolts while running, 

i have checked the windings and all is fine connections are correct, what would cause this?


----------



## oliquir (Jan 13, 2011)

vsd could limit current and stop accelerating when current is reached, probably a bad parameter somewhere. i would reset vsd to default then reconfigure


----------



## John Valdes (May 17, 2007)

Is your motor 12 lead?
If you wire it in a star config, when it should be connected delta, you are only producing about 1/2 of the motor HP.
The load may be sufficient to not allow this motor to turn it. Do not let the current reading reassure you. 
So wire the motor for delta run and do what oliquir said above.
Reset drive to factory settings and reconfigur the parameters. Run the auto tune function also. 
Make sure you input the motor nameplate info as this is very important.


----------



## devil0808 (Nov 18, 2014)

hi
i will check and see what amps the motor is drawing, i have factory defaulted the vsd i cant figure out why in star it runs up to speed and down again just fine but when i put it in delta its unhappy, next option is put another 4kw motor on and test if it does the same, contacted local siemens agent and they refurd me to germany,
what does he mean when he asks for"A foto from the motor platte and a starter or drive monitor project.
Datas from the MM440 (Kw with Hhigh overload)."

motor i understand but starter /drive monitor project?


----------



## devil0808 (Nov 18, 2014)

John Valdes said:


> Is your motor 12 lead?
> If you wire it in a star config, when it should be connected delta, you are only producing about 1/2 of the motor HP.
> The load may be sufficient to not allow this motor to turn it. Do not let the current reading reassure you.
> So wire the motor for delta run and do what oliquir said above.
> ...


it is 6 lead, and yes star config is giving me less HP thats why i think i am not getting rotation in star(keep in mind motor connected direct on line threw contactor in star runs fine). motor plate is missing, all i can go on is basic 4kw motor infomation, only thing i was not sure of when setting up was cos0.82 i have set it up and down (viewing ranges of other 4kw motor in factory)
siemens has such a complicated setup for autotune they want motor running at 80% and tuning takes like 10 minutes, but motor is not running at 80% when i turn up the hz to 40 so scared i pop the inverter

last week had new ABB vsd setup was a breeze followed motor and voltage settings AI1 reference was working via 5k pot remote di1 was not setup for start/stop and factory locking up so i decide to quickly test, i put it into local and wanted to run it, the next moment the inverter explodes shot the fan right out of enclosure like a gun shot. i dont want the same situation so i am so carefull now.
i have setup quite a few different brands weg,varispeed but never had issues before this month.


----------



## JRaef (Mar 23, 2009)

If you are attempting to use it at the reduced HP in Star (bad idea to begin with) you would need to trick the VFD into thinking it is the lower voltage than the nameplate says it is. So I'm going to guess (because you force me to by not providing details) that this is a 400V motor intended to be connected in Delta, so my connecting in Star, you are getting 58% of the power from it. But from the VFD standpoint if you program the VFD telling it that the motor is 4kW motor rated for 400V 50 Hz, then the V/Hz ratio is 8:1. When you then connect it in Star, the EFFECTIVE voltage would be 230V 50Hz with the capacity de-rated to 2.3kW, and the V/Hz ratio SHOULD BE 4.6:1. But because you entered the incorrect voltage into the drive parameters, it is saturating the motor, then the VFD goes into current limit to prevent damage, which overrides your commanded speed and stops at some low value, like 10Hz. 

Connect the motor in the manner it is supposed to be connected as per the nameplate. The idea of saving anything by connecting in Star is a falsehood to begin with, although widely done in some counties for some reason. The VFD itself will match the motor power to the pump requirements, playing a game with the motor corrections is pointless and dangerous, because in addition to reducing the power capacity of the motor, you also create a high slip condition that can potentially damage it. Lucky for you the VFD prevented that.

If by chance you DID know all this and execute it correctly by telling the VFD it is a 230V motor that is 2.3kW, then you have a bad motor, likely damaged by having that done to it in the past.


----------



## devil0808 (Nov 18, 2014)

hi

ok the motor is 4kw 3phase(it has no name plate and on other drives i have one simular motor working fine)


the weg vsd is connected delta, 400volt, 9kw works fine
the siemens vsd, delta, 400volt, 4kw works fine



its just this siemens vsd i am busy with wont work like that with exactly the same parameters for the motor, you have a point it might be current limiting i set the current to 9 and overload percentage is 150% as per default and other siemens vsd is set the same.

i am connecting up another motor to vsd today, gonna try go threw the 3900 parameters vurses the other siemens vsd i have running

only motor parameter i dont know is COSphi(viewing other motor settings i set it to 0.82) would this have great effect?


----------



## devil0808 (Nov 18, 2014)

ok so problem is solved, fault in the end was the motor!! jip somethings is wrong with it or its partially blown but spare motor runs up like a dream, connected to monopump and its running fine draws 4.5amp dont need to boost it so i would like to thank John Valdes,JRaef and Oliquir for your input its always tough when things go wrong and your out of ideas. anyways i now have to find a new refractometer for the evaporator.


----------

