Asynchronous Squirrel-Cage Induction Motors

Downloads:

The following instructions apply to Asynchronous Squirrel-Cage Induction Motors.

Induction motors standard operating procedures. (PDF - 800kb)

IP rating for equipment. (PDF - 100kb)

GENERAL

SAFETY INSTRUCTIONS

Your attention is specifically drawn to all items marked which are very important to safety or the avoidance of damage to the motor.

The Electrical Machines described here, form part of power installations for industrial applications and are designed in accordance with generally accepted engineering practice. When incorrectly used, wrongly operated, insufficiently serviced, or in the case of unauthorised modifications, machines of this type may cause serious personal injury or material damage to the plant because of the electrical and mechanical conditions prevailing during operation.

The general criteria regarding appropriate use of the motors (i.e. installation, connection, ambient and operating conditions) is specified by the standardised technical data given on the rating plate, in the catalogue or in the contract documents and must be strictly adhered to. If there are any problems, particularly in the case of missing product related information, the necessary verification must be obtained via the relevant sales office. Please always mention the machine type and serial number.

Where higher degrees of safety are required, for use in non-industrial areas (e.g. touch guards to prevent access by children's fingers or the like), these conditions must be established by the user during installation of the machines and thus provide additional protective measures.

This means that these operating instructions are only for industrial applications. Furthermore, the applicable national, local and plant-specification regulations and requirements must be adhered to.

It is assumed that the planning and execution of the mechanical and electrical installations, lifting, erection and commissioning as well as the maintenance and repair work required during the installation be carried out, or is supervised by qualified personnel who are trained and authorised for this task. This refers both to the observance of the general erection and safety regulations for work on power installations, to the correct use of hoisting gear and tools and, if necessary, to the use of personal protective gear such as safety boots and the like.

These instructions do not purport to cover all details or variations in equipment, nor to provide for every possible contingency encountered with installation, operation or maintenance. if in doubt we recommend calling for assistance from the relevant sales office.

TRANSPORT

Each machine must only by lifted by the eye bolts! The hoisting gear used must be suitable for the machine mass (see rating plate). Use suitable sling protectors or spreading devices to avoid damage to machine mounted accessories.

The eye bolts are sized for the motor mass only. if the driven equipment e.g. a pump, is assembled to the motor, then additional lifting facilities must be used to hoist the assembly.

if the motors are mounted on baseplates, as a part of a machine set, the entire assembly must be lifted from the baseplate and not from the motor.

The rotor of machines with cylindrical roller bearings or angular-contact ball bearings is locked in position for transport by a shaft clamp to prevent damage to the bearing due to brinelling. n Do not remove this shaft clamp until the transmission element is fitted. In special cases, if the machine is to be transported after the transmission element has been fitted, other measures will be necessary to secure the rotor. This is the responsibility of the equipment manufacturer.

Vertical machine types with angular-contact ball bearings should then be transported in the vertical position. if horizontal transport should become necessary in exceptional cases, lock the rotor in position by a shaft clamp before carefully moving the machine into a horizontal position.

Flange mounted machines or foot-flange machines with large diameter flanges need to be transported and stored with adequate support under the frame to prevent the motor being supported on its cowl.

RECEIPT

Examine the motor on receipt for transit damage and advise the sales office of any damage detected. Damaged packing cases - open in the presence of an insurance surveyor. Ensure free rotation of motor shaft, if not clamped. Rotation - large 2 pole motors (280 size and above) may be uni-directional. Check from indication arrow that motor suits the drive. Terminal Entry - check that this is on the correct side of the motor and that the conduit hole is of the required size.

HANDLING

Ensure that the eyebolt is screwed firmly into the frame up to the eyebolt shoulder. With horizontally mounted motors, lifting should be vertical from the eyebolt. Motors for vertical shaft applications should be lifted vertically by the eyebolt or by the trunnion arrangements provided. Eyebolts provided on flange mounted motors are only suitable for taking motor mass, and must be lifted in accordance with the well known safety regulations where a spreader is used.

Machines for some vertical pad mounted applications, where a fan is fitted, may have a hole in the shaft extension specifically provided for the fitting of an eyebolt, thus enabling the motor to be lowered into the fan ducting. Care must be taken to ensure that any fitment or attachment to the motor does not exceed the total load capacity of the eyebolt being used for the assembly.

STORAGE

If a machine is not put into service immediately after arrival, store it in a clean dry room which is not subject to extremes of temperature and I or humidity that may result in condensation inside the motor. Motors should be stored away from corrosive or chemically damaging fumes.

If heaters are fitted to the motor, these must be energised. Any open terminal box cable entry holes should be sealed off to prevent vermin or moisture ingress.

Motors should not be stored in positions where they could be subjected to vibration, as brinneling or fretting corrosion may occur within the bearings, causing noise and premature failure in service.

Motors with shaft clamps should have these removed during storage so that the shafts can be rotated.

In order to limit any premature bearing failure and hardening of the grease, shafts should be rotated monthly by a quarter of a revolution and every three months by at least 10 revolutions to re-establish the protective film of lubricant on the bearing surfaces. More frequent rotations (every week) are advisable where vibration levels are of concern.

In long term storage, up to 24 months, grease-lubricated rolling bearings should be over filled with the approved grease. This will prevent moisture entering the bearing and any surplus grease will be expelled once the machine is started. At the 12 month interval inject a fresh quantity (as per rating plate) of grease into the bearing assembly. In all cases, after greasing, the shaft should be turned at least 10 revolutions by hand.

If motors are stored for more than 24 months it is advisable to flush out the old lubricant with white spirits and re-grease and pack the housing before being put into service.