Thermal Protector Information; Changing Rotation; Reduced Voltage Starting; Operation - ABB M2B Serie Manual De Instalación, Manejo Y Mantenimiento

2.8 Thermal protector
information
Motors have as standard class F, normally closed
thermostats connected in series in the stator winding.
Thermistors, rated 150°C, connected in series are also
provided as standard. Other types of thermal protection
are available on request.
If the motor has separate connection diagrams, follow
the instructions given.

2.9 Changing rotation

1. Keep hands and clothing away from rotating parts.
2. Before the motor is coupled to the load, determine
proper rotation.
3. Check rotation by jogging or bumping. Apply power
to the motor leads for a short period of time, enough
to just get motor shaft to rotate a slight amount to
observe shaft rotating direction.
4. Three phase - interchange any two (2) of the three
(3) line leads. Single phase - reconnect per the
connection diagram on the motor.

2.10 Reduced voltage starting

Motors used on reduced voltage starting should be
carefully selected based upon power supply limitations
and driven load requirements. The motor's starting
torque will be reduced when using reduced voltage
starting. The elapsed time on the start step should be
kept as short as possible. Refer to ABB for application
assistance.

3. Operation

Warning
Disconnect and lock out before working on motor or
driven equipment.
Windings should be discharged immediately after
measurement to avoid risk of electric shock.

3.1 Before initial starting

1. Measure insulation resistance before commissioning
and when winding dampness is suspected:
Resistance, measured at 25°C (77°F) , shall exceed
the reference value, ie
R ≥
20 x U M ohm (measured with
1000 + 1.5P 500 V dc Megger)
where U = voltage, P = output power, HP.
Warning
Windings should be discharged immediately after
measurement to avoid risk of electric shock.
Insulation resistance is halved for each 20°C rise in
ambient temperature.
6
2. If the reference resistance value is not attained, the
winding is too damp and must be oven dried. Oven
temperature should be 90°C (194°F) for 12-16 hours
followed by 105°C (223°F) for 6-8 hours.
Drain hole plugs, if fi tted, must be removed during
heating.
Windings drenched in sea water normally need to be
rewound.
3. See that voltage and frequency stamped on motor
and control name plates correspond with that of the
power line.
4. Check all connections to the motor and control with
the wiring diagram.
5. Be sure rotor turns freely when disconnected from
the load. Any foreign matter in the air gap should be
removed.
6. Leave the motor disconnected from the load for the
initial start. It is desirable to operate the motor
without load for about one hour to test for any
localized heating in bearings and windings. Check
for proper rotation. Check for correct and balanced
voltage at the motor terminals. Check no load amps.
3.2 Allowable voltage and
frequency range
If voltage and frequency are within the following range,
motors will operate, but with somewhat different
characteristics than obtained with correct name plate
values.
1. Voltage: Within 10% above or below the value
stamped on the name plate. On three phase
systems the voltage should be balanced within 1%.
A small voltage unbalance will cause a signifi cant
current unbalance.
2. Frequency: Within 5% above or below the value
stamped on the name plate.
3. Voltage and frequency together: Within 10%
(providing frequency above is less than 5%) above
or below values stamped on the name plate.

3.3 Operation with inverters

When a squirrel cage motor is used with an inverter the
following must be done:
1. Always check:
a. The motor and inverter ratings.
b. Insulation level of motor.
c. Earth connection of motor and the driven
equipment.
2. Check if the motor will be operating at high speeds:
a. Bearing type and lubrication.
b. Fan characteristics.
c. Critical speeds.
d. Maximum torque.
3. Check if the motor will be operating at low speeds:
a. Bearing type and lubrication.
b. Motor's cooling system.
c. Magnetic noise.
ABB / Low Voltage NEMA Motors / Manual 03-2006