General operating instructions, installation and commissioning

Roots pumps must be exactly level. When attaching the pump it is necessary to ensure that the pump is not under any tension or strain whatsoever. Any strains in the pump casing caused by the connection lines shall be avoided. Any strain to which the pump is subjected vi/ill endanger the pump since the clearances inside the roots pump are very small. 

Roots pumps are connected to the line power supply via the motor terminal 

The direction of motor rotation shall be checked with the intake and outlet ports open prior to installing the pump. The drive shaft, seen from the motor end, must rotate counter-clockwise. Note the arrow on the motor indicating the direction of rotation If the roots pump runs in the vwong direction, then it is reversed by interchanging two of the phases at the motor connection cord. 

The roots pump may be switched on only after the roughing pump has evacuated the vacuum vessel down to the cut-in pressure. 

Permissible cut-in pressure will depend on the reduction ratios of the roots pump as against the roughing pump and is calculated by dividing the permissible pressure differential Ap, g by the compression ratio, reduced by the value of 1  

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