porky Posted January 20, 2007 Report Share Posted January 20, 2007 Driving a Cryogenic pump motor, the motor rating plate states that the Nominal Voltage is 400V, 6090 RPM and 101,5 Hz. It also states that the motor may run between 62 and 110 Hz with a speed of 3700 to . I think 6900 Rpm... not too sure on the actual value. I programmed the nominal rated frequency and RPM into the drive and the motor just kept on shuting down within seconds of starting .... the only fault it indicated was overbraking..... Im lost... since over braking should not apply at start up... I played around with the settings and set the rated motor frequency at 62 Hz and the RPM at 3700 .....and it works well no problems at all.... I am still confused as to why it would not work with the correct name plate settings. Can anyone shed some light... Link to comment Share on other sites More sharing options...
mariomaggi Posted January 21, 2007 Report Share Posted January 21, 2007 Dear porky, the unit must work, but we have not enough data to give you the right suggestion. Maximum theoretical speed will be 6600 RPM at 110 Hz Asyncron motor or synchron motor? From the nameplate (6090/101.5 = 60.0000) it seems to be a synchron type). New installed unit or old unit? Inverter manufacturer and type? Supply voltage? Setting of acceleration ramp time? Regards Mario Mario Maggi - Italy - http://www.evlist.it - https://www.axu.it Link to comment Share on other sites More sharing options...
porky Posted January 21, 2007 Author Report Share Posted January 21, 2007 Dear porky, the unit must work, but we have not enough data to give you the right suggestion. Maximum theoretical speed will be 6600 RPM at 110 Hz Asyncron motor or synchron motor? From the nameplate (6090/101.5 = 60.0000) it seems to be a synchron type. it is a sycron motor New installed unit or old unit? Brand new manufacturer and type? Altivar61 Supply voltage? 400Vac Setting of acceleration ramp time? 8 seconds, but I did try several different times but still had the same result Regards Regards Mario Link to comment Share on other sites More sharing options...
porky Posted January 22, 2007 Author Report Share Posted January 22, 2007 hi Just a querry, with respect to my previous question, From the attachment what would you put as the nominal speed and frequency and voltage in the program? and what is meant my weakening frequency ? Many thanks PaulSEFCO.pdf Link to comment Share on other sites More sharing options...
jraef Posted January 23, 2007 Report Share Posted January 23, 2007 First off, in the VFD, speed is only relevant in the way the drive displays the operating speed. The motor parameters are set up by the voltage and frequency. From what I see on that nameplate, I would say that this motor is rated for 110Hz at 400V, but that seems to contradict what you have experienced. The field weakening point is confusing though. Usually the field weakening point is just above the synchronous speed, because at that point you have no more voltage to give to the motor so you begin operating in a constant power mode, losing torque as you increase frequency above that point. If that were the case then, that would make me think the design frequency of the motor was 100Hz then. It could be that this nameplate is really denoting the operating range of the entire pump as a unit, not the specifics you need for programming the VFD. It is saying that although the pump can be operated between 62 and 110Hz, once you go over 101.5Hz you will be losing torque. If on the other hand it was in fact a 62Hz designed motor as your experiment seems to indicate, then your Field Weakening point would be around 62.5Hz and by the time you got to 110Hz you would have very little torque left in that motor. Now I am as confused as you. Sorry. I think this is a question to be discussed with the motor or the pump manufacturer if possible. That is a very non-standard nameplate to my experience. "He's not dead, he's just pinin' for the fjords!" Link to comment Share on other sites More sharing options...
AB2005 Posted January 23, 2007 Report Share Posted January 23, 2007 I think this is a question to be discussed with the motor or the pump manufacturer if possible. That is a very non-standard nameplate to my experience. I agree with Mr. Jreaf. This is very strange Name plate, f range = 62-110HZ and field weakening point = 101.5HZ. "Don't assume any thing, always check/ask and clear yourself". Link to comment Share on other sites More sharing options...
kens Posted January 23, 2007 Report Share Posted January 23, 2007 Hi Porky, as stated earlier that seems to be a pretty unique nameplate. Out of interest i had a look at their website but i found it short on tech info and long on large glossy brochures. Try the link below for their service department and they should be able to help. http://www.sefco.ch/Contacts/contactsform2.htm Ken An expert is one who knows more and more about less and less until he knows absolutely everything about nothing Link to comment Share on other sites More sharing options...
mariomaggi Posted January 23, 2007 Report Share Posted January 23, 2007 porky, you don't supplied enough data, the motor is not identified (100 W? 30 kW?) Also the inverter size is not known. One possibility is the wrong coupling between such synchron motor and such drive. Don't forget that Altivar 61 has a limited possibility to supply current, being a HVAC inverter. Regards Mario Mario Maggi - Italy - http://www.evlist.it - https://www.axu.it Link to comment Share on other sites More sharing options...
porky Posted January 23, 2007 Author Report Share Posted January 23, 2007 porky, you don't supplied enough data, the motor is not identified (100 W? 30 kW?) Also the inverter size is not known. One possibility is the wrong coupling between such synchron motor and such drive. Don't forget that Altivar 61 has a limited possibility to supply current, being a HVAC inverter. Regards Mario ............Take a look at the attachment that I placed on my second posting ...it has all the information tha you requested. Link to comment Share on other sites More sharing options...
marke Posted January 23, 2007 Report Share Posted January 23, 2007 Hello Porky Firstly, if the motor is a synchronous motor with a permanent magnet rotor, you may need to alter the drive settings to suit. Some drives are designed to operate with induction motors only, others are designed to operate with induction motors, and permanent magnet motors. There will be a parameter that need to be set for this. With an inductive component, in order to maintain a constant flux in the iron, we use a constant V/Hz ratio. Below the nominal frequency, we reduce the voltage with the frequency such that the ratio of V/Hz is the same as at the rated voltage and frequency. As we increase the frequency above the rated frequency, we can not increase the voltage because it is limited by the input voltage. This results in a reducing flux at higher frequencies. This can be known as field weakening, but this is usually applied to DC motors rather than induction motors. I would suggest that you set the rated frequency as equal to the field weakening frequency and the rated voltage at 400Hz. Best regards, Mark Empson | administratorSkype Contact = markempson | phone +64 274 363 067LMPForum | Power Factor | L M Photonics Ltd | Empson family | Advanced Motor Control Ltd | Pressure Transducers | Smart Relay | GSM Control | Mark Empson Website | AuCom | Soft Starters Link to comment Share on other sites More sharing options...
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