Induction motors are fitted with ball and or roller bearings. These bearings are robust and reliable and should give very little trouble provided they are properly fitted, kept abs... Read more
The maintenance requirements for cage-rotor induction motors are very simple: contact resistance low Keep insulation resistance high and Lubricate correctly and maintain a uniform... Read more
Low power motors for power tools, domestic equipment, refrigerators, vacuum cleaners etc are typically supplied at 220V a.c. 50/60Hz. Common types are: Split-phase induction motor... Read more
ships, voltages upto and equal to 1000 volts is called as low voltage system and voltages above 1000 volts is called high voltage system. Normally low voltage system is common on b... Read more
The two systems dominating the market today are Frequency controlled A.C Motors and SCR controlled D.C Motors. Frequency controlled A.C Motor drive system were generally more cost... Read more
There are three types of overcurrent relay (OCR) used for motor protection: Electronic Thermal Electromagnetic Electronic OCIT (overcurrent inverse time) relays have largely supers... Read more
Protecting an electric motor basically involves preventing the motor from getting too hot. Remember, every 10*C above the maximum recommended temperature of the insulation can redu... Read more
The standard cage-rotor a.c. induction motor operates as an almost constant speed drive over its load range. This feature is satisfactory for most of the ship’s auxiliary ser... Read more
When motor direct-on-line started with the stator winding star connected, it will only take one-third of the starting current that it would take if the windings were delta connecte... Read more
When the 3-phase a.c. supply voltages are connected to the three stator phase windings, the resulting phase currents produce a multi-pole magnetic flux. This flux is physically rot... Read more
