An unbeatable one-two combination

Kaeser paved the way for the high­est cur­rent effi­cien­cy gain, and thus reduced ener­gy costs, when using vari­able-speed com­pres­sors. Fol­low­ing the ASD series, the CSD/CSDX series has now been equipped with this inno­v­a­tive dri­ve technology.

Respon­si­ble use of resources is one of the key fac­tors to which Kaeser Kom­pres­soren owes its suc­cess. As a lead­ing com­pressed air sys­tems provider and a renowned indus­try trend­set­ter, the fam­i­ly-owned com­pa­ny proud­ly pre­sent­ed yet anoth­er tech­no­log­i­cal mile­stone some time ago: the intro­duc­tion of syn­chro­nous reluc­tance motors for its SFC vari­able-speed screw com­pres­sors. Fol­low­ing the ASD series, the CSD and CSDX series have now been equipped with this tech­nol­o­gy as well. This means sig­nif­i­cant­ly low­er ener­gy costs for cus­tomers, par­tic­u­lar­ly in the cru­cial par­tial-load range, com­pared to the pre­vi­ous solu­tion with asyn­chro­nous motors.

With Sig­ma Pro­file and inno­v­a­tive dri­ve con­cepts, Kae­ser’s rotary screw com­pres­sors already deliv­er out­stand­ing per­for­mance and reli­a­bil­i­ty, com­bined with ener­gy effi­cien­cy and space-sav­ing design, in keep­ing with Kae­ser’s mot­to: More com­pressed air for less ener­gy con­sump­tion. The roll-out of syn­chro­nous reluc­tance tech­nol­o­gy was the next step towards even greater effi­cien­cy. The major advan­tage of this com­plete solu­tion, which was devel­oped in part­ner­ship with Siemens, is an effi­cien­cy gain of approx­i­mate­ly ten per­cent in the par­tial-load range. Thanks to the inno­v­a­tive motors and the top IES2 clas­si­fi­ca­tion as per the new EN 50598 effi­cien­cy stan­dard, this solu­tion offers unprece­dent­ed effi­cien­cy. For exam­ple, in the case of an ASD SFC series screw com­pres­sor, this trans­lates into aver­age ener­gy cost sav­ings of around 450 euros per year, based on approx­i­mate­ly 6,000 oper­at­ing hours at a rate of 10 cents per kilo­watt hour. Users there­fore not only enjoy max­i­mum flex­i­bil­i­ty for spe­cif­ic appli­ca­tions and vary­ing envi­ron­men­tal con­di­tions, but also with regard to load response.

Variable-speed drive with high system efficiency

Com­pressed air sta­tions are often con­struct­ed on a mod­u­lar basis. Con­tin­u­ous­ly run­ning com­pres­sors with IE4 motors cov­er base load demand, whilst addi­tion­al peak-load com­pres­sors respond flex­i­bly to meet extra demand; the sys­tem is con­trolled by a Sig­ma Air Man­ag­er 4.0 to ensure max­i­mum effi­cien­cy. With the Siemens syn­chro­nous reluc­tance dri­ve sys­tems, this will be per­formed with even greater effi­cien­cy in the all-impor­tant par­tial load range.

They were devel­oped in response to the fact that the new EN 50598 eco-design stan­dard applies not only to the effi­cien­cy val­ues of indi­vid­ual dri­ves, but rep­re­sents a shift in reg­u­la­to­ry empha­sis to over­all sys­tem effi­cien­cy and thus assess­es the com­pli­ance of vari­able-speed dri­ve solu­tions, based on their over­all sys­tem effi­cien­cy. With its vari­able-speed ver­sion (SFC) of the ASD to CSDX series, Kaeser paves the way for cus­tomers around the world to embark on a path of min­i­mal ener­gy con­sump­tion and min­i­mal oper­at­ing costs.

Synchronous and asynchronous motor technology

This new and inno­v­a­tive series of gen­er­al-pur­pose motors com­bines the strong points of both asyn­chro­nous and syn­chro­nous motors in a sin­gle dri­ve sys­tem. No alu­mini­um, cop­per or expen­sive rare earth mag­nets are used in the rotors. Instead they are made of elec­tri­cal steel with a spe­cialised pro­file and arranged in series, mak­ing the dri­ve high­ly durable and main­te­nance friend­ly, the char­ac­ter­is­tic advan­tages of asyn­chro­nous motors.

On the oth­er hand, the con­trol prop­er­ties of the new motors are com­pa­ra­ble to those of syn­chro­nous motors. The spe­cial rotor design enables reluc­tance motors to deliv­er high speeds with­out addi­tion­al rotor warm­ing due to cur­rent flow. The key to this lies in opti­mised match­ing of the dri­ve sys­tem ele­ments, i.e. the motor and fre­quen­cy con­vert­er. It is the per­fect­ly har­monised inter­play between these two com­po­nents that facil­i­tates max­i­mum ener­gy savings.