Screw compressor

Abstract

The invention revealed a screw compressor and its electrical control system and related control methods. The system comprises a power module, a high-low (tension) transformer and a compressor wiring control circuit. The high-low (tension) transformer connects the power module to provide at least two different voltages: low voltage and high voltage; the compressor wiring control circuit connects said high-low (tension) transformer to control the switching and connection mode of said wiring terminals of the compressor; When the first voltage is connected to the screw compressor, the connecting circuit formed by the wiring terminals which are controlled by a connecting unit will be in the first status. When the second voltage is connected to the screw compressor, the connecting circuit formed by the wiring terminals which are controlled by a connecting unit will be in the second status. The electrical control system of the compressor revealed by the invention can easily realize the switching of low and high voltage by changing the jumpers on the wiring terminals of the patch board with no need to change the connection mode of the motor.

1 . A screw compressor, wherein its electrical control system comprises a power module, a high-low (tension) transformer which connects said power module to provide at least two sets of different voltages, namely the first voltage and the second voltage.
 a screw compressor wiring control circuit connects said high-low (tension) transformer to control the switching of said wiring terminals and the connection mode.   said screw compressor wiring control circuit controls the switching of said wiring terminals and the connection mode by a connecting unit. When the first voltage is connected to the screw compressor, the connecting circuit formed by said wiring terminals which are controlled by said connecting unit will be in the first status. When the second voltage is connected to the screw compressor, the connecting circuit formed by the wiring terminals which are controlled by said connecting unit will be in the second status.   
     
     
         2 . The screw compressor according to  claim 1 , wherein said electrical control system comprises a frequency converter to control said compressor in the status of frequency conversion and said frequency converter is controlled by a control circuit. 
     
     
         3 . The screw compressor according to  claim 1 , wherein said wiring terminals connect machine winding; said connecting units control the switching of said wiring terminals and the connection mode to further control that of the machine winding; The machine winding is in parallel by said connecting unit when the first voltage is connected to the screw compressor; The machine winding is in series by said connecting unit when the second voltage is connected. 
     
     
         4 . The screw compressor according to  claim 3 , wherein the machine winding is in parallel by said connecting unit when the low voltage is connected to the compressor; the machine winding is in series winding by said connecting unit when the high voltage is connected. 
     
     
         5 . The screw compressor according to  claim 1 , wherein said connecting unit is a jumper, then the switching of said wiring terminals of the compressor and the connection mode are controlled by the jumper. 
     
     
         6 . The screw compressor according to  claim 5 , wherein the machine winding is in parallel by said connecting unit when the first voltage is connected to the screw compressor; the wiring terminals of the compressor are short connected in a pairwise way by the jumper. 
     
     
         7 . The screw compressor according to  claim 6 , wherein said wiring terminals of the compressor are short connected, namely U 1  and U 5 , U 2  and U 6 , V 1  and V 5 , V 2  and V 6 , W 1  and W 5 , W 2  and W 6 , among which U 1  connects the signal of Ua, U 6  connects the signal of Ub, V 1  connects the signal of Va, V 6  connects the signal of Vb, W 1  connects the signal of Wa, W 6  connects the signal of Wb. 
     
     
         8 . The screw compressor according to  claim 7 , wherein the wiring terminals of the screw compressor, namely U 1  and U 5 , U 2  and U 6 , V 1  and V 5 , V 2  and V 6 , W 1  and W 5 , W 2  and W 6  shall be short connected by some jumpers; meanwhile, the spacers shall be set between U 5  and U 2 , V 5  and V 2 , W 5  and W 2 . 
     
     
         9 . The screw compressor according to  claim 8 , wherein said jumpers and spacers shall be set in an integrated way according to the positions of the wiring terminals of the screw compressor. 
     
     
         10 . The screw compressor according to  claim 7 , wherein the wiring terminals U 5  and U 2 , V 5  and V 2 , W 5  and W 2  shall be short connected by the jumpers when second voltage is connected to the compressor. 
     
     
         11 . The screw compressor according to  claim 10 , wherein said jumpers shall be set in an integrated way according to the positions of the wiring terminals of the screw compressor. 
     
     
         12 . The screw compressor according to  claim 1 , wherein said electrical control system comprises some relays which are respectively controlled by different control circuits. 
     
     
         13 . The screw compressor according to  claim 1 , wherein said electrical control system also comprises via circuit which is set between said power module and high-low (tension) transformer; said electrical control system comprises a safing circuit between said power module and high-low (tension) transformer. 
     
     
         14 . The screw compressor according to  claim 1 , wherein the inlet terminals of the said high-low (tension) transformer, No. 4 connects No. 6 and No. 1 connects No. 6, then the transformer outlets the first voltage; the inlet terminals of the said high-low (tension) transformer, No. 1 connects No. 6, then the transformer outlets the second voltage; said first voltage is low voltage and said second voltage is high voltage. 
     
     
         15 . An electrical control method of a screw compressor according to any claims from  1 , wherein said compressor wiring control circuit control the switching of said wiring terminals and the connection mode through a connecting unit; the wiring circuit formed by said wiring terminals of the connecting unit is in the first status when the first voltage is connected to the screw compressor and it is in the second status when the second voltage is connected; 
     
     
         16 . The electrical control method of a screw compressor according to  claim 15 , wherein said electrical control system comprises a frequency converter to control said compressor in the status of frequency conversion and said frequency converter is controlled by a control circuit. 
     
     
         17 . The electrical control method of a screw compressor according to  claim 15 , wherein said wiring terminals connect machine winding; said connecting units control the switching of said wiring terminals and the connection mode to further control that of the machine winding; The machine winding is in parallel by said connecting unit when the first voltage is connected to the screw compressor; The machine winding is in series by said connecting unit when the second voltage is connected. 
     
     
         18 . The electrical control method of a screw compressor according to  claim 15 , wherein said connecting unit is a jumper through which the switching of said wiring terminals of the compressor and the connection mode are controlled. 
     
     
         19 . The electrical control method of a screw compressor according to  claim 15 , wherein the machine winding is in parallel by said connecting unit when the first voltage is connected to the screw compressor; the wiring terminals of the compressor are short connected in a pairwise way by the jumper. 
     
     
         20 . The electrical control method of a screw compressor according to  claim 15 , wherein said methods involve the procedures of replacing motors with different specifications.