Please refer to the following example for single unit and multiple unit applications and model selection. The REG2000 supports a maximum of 4 units working in parallel at the same time with each unit automatically reducing its current limit to 80%.
Model selection method for single unit application (crane/hoist)
System: AC motor drive model VFD075CH43A with a 5.5kW motor.
1.Assume motor efficiency=85%, mechanical efficiency=85%, AC motor drive=95% and REG2000=95%. Calculate the useful power output as:
5.5kW*0.85^2*0.95^2=3.57kW
2.When using the REG2000, if the mains voltage is 380V, the output current would be: 3.57kW/(sqrt(3)*380V)= 5.4 A
3.From the diagram below, at 40% ED, and a working duration of 150s, the output current must be lower than 90% of the rated current to prevent overloading.
4.Refer to the REG2000 product specifications in its brochure or manual to select a suitable model. Model (REG075A43A-21) provides a rated current of 10.5A. Calculate the supporting capacity as:
10.5A*90% = 9.45A
Since it is larger than 5.4A, the user can choose model REG075A43A-21 for this application.
Model selection method for multiple unit application (crane/hoist)
System: AC motor drive model VFD132CH43A with 112kW motor
1.Operation time: vertical movement (upward/downward)= 20~30sec, horizontal movement ( scrap metal grapple)= 20~30sec, operation time per cycle= 90sec, %ED= 30/90 x 100% = 33%
2.Assume motor efficiency=85%, mechanical efficiency=85%, AC motor drive=95% and REG2000=95%. Calculate the useful power output as:
112kW*0.85^2*0.95^2=73 kW
3.When using the REG2000, if the mains voltage is 440V, the output current would be: 73kW/( *440V)=95.8 A
Since it is larger than one REG2000 can support, then parallel connection is required to expand total capacity.
4.Under parallel connection, each REG2000 will reduce its current limit to 80% automatically. Refer to the explanation below for setting parallel mode.
5.Refer to the REG2000 product specification in its brochure or manual to select a suitable model. The 45kW model (REG450A43A-21) provides a rated current of 60A and two units would provide sufficient capacity for this application. Calculate the supporting capacity as:
60A*2*80%=96
Since it is larger than the output current 95.8A, the user can choose two REG450A43A-21 units for this application.
