Lenze SMD Frequency Inverters Unstick Glue Production
Costly downtime reduced on PVA emulsion pumps
Lenze's SMD inverters have solved a problem of costly downtime, as a result of motors burning out on PVA emulsion pumps at Grosvenor Chemicals, which manufactures a diverse range of chemicals and pharmaceutical intermediates at its UK plant.
The PVA emulsion pumps are used in the production of glue at Grosvenor's Huddersfield factory. Previously they were driven by fixed speed electric motors, which had problems resulting from the variation in PVA emulsion viscosity across different products. This was causing motor overloads, particularly on restarts, with the consequent problems of premature motor failures, and costly downtime.
The solution to this problem was Lenze VFD inverters. These were supplied in very compact panels – an arrangement possible due to the very small footprint of the smd series (only 114mm x 171mm for 5.5kW). The inverters are rated at 5.5kW and 7.5kW; and are equipped with a footprint filter to meet RFI class 'A' requirements. A separate keypad is door mounted to give the operators an easy way to change the pump speed.
The smd units provide a soft start facility for the pump motors, and can hold 150% rated torque for up to 60 seconds. They also provide further protection via their built-in thermal motor monitoring, which allows a shutdown with error message if the motor begins to overheat, without causing any motor change.