Carrier 17 Start Up & Operation Manual

Contents

NOTE: When operating flood-lubricated sleeve bearings,the bearing temperature must not be allowed to exceed185 F (85 C) total temperature.Under normal conditions, for the self-lube bearing,the rate of temperature rise should be from 20° to25° F (11° to 14° C) for the first 10 minutes afterstarting up and approximately 40° F (22° C) at30 minutes. The rate of bearing temperature rise isa function of the natural ventilation and operatingconditions.When the rate of bearing temperature rise is less than2° F (1.1° C) per half-hour, the bearing temperatureis considered to be stabilized.If the total bearing temperature exceeds 195 F(91 C), the motor should be shut down immediately.3. Any abnormal noise or vibration should be immediatelyinvestigated and corrected. Increased vibration (with themotor uncoupled from its load) can be indicative of a changein balance due to a mechanical failure or the loosening ofa rotor part, a stator winding problem, foundation prob-lem, or a change in motor alignment.4. Verify that the magnetic center indicator aligns with theshaft.Initial Coupled Start-Up — After initial uncoupled start-up,the following steps should be taken to ensure safe coupledoperation:1. Follow the procedure stated in General Maintenance,Machine Alignment section to align the motor to the drivenmachine.2. Prepare the coupling for operation in accordance with thecoupling manufacturer’s instructions. Note any match markson the couplings and assemble accordingly. For sleevebearing motors, verify that the correct limited endfloatcoupling has been installed. The endfloat limits can befound on the certified drawing.3. Ensure that all personnel are at a safe distance from ro-tating parts. Start the motor in accordance with instruc-tions supplied with the motor control.4. If the motor rotor fails to start turning in a second or two,shut off the power supply immediately. This can resultfrom:a. Too low a voltage at the motor terminals.b. The load is too much for the rotor to accelerate.c. The load is frozen up mechanically.d. All electrical connections are not made.e. Single phase power has been applied.f. Any combination of the above.Investigate thoroughly and take corrective action beforeattempting a restart.5. Carefully observe the vibration of the bearing housing andany abnormal noise generator.Note that motor vibration may not be identical to the un-coupled values. If coupled vibration is excessive, re-check the mounting and alignment.6. Carefully observe the bearing temperature rise and themovement of the oil ring.If the bearing temperature rise and motor operation ap-pear normal, operation should continue until the bearingtemperatures stabilize.7. If possible, check the motor line currents for balance.It should be recognized that each start of an induction mo-tor subjects the motor to full inrush current with resultingheating of the stator and rotor windings. Each accelerationand repeated starts can produce more heat than is producedand dissipated by the motor under full load. The starting dutyfor which the motor is designed is shown by a nameplatemounted on the motor and must not be exceeded, if longmotor life is expected. Abnormally low terminal voltage, ex-cessive load torque and/or excessive load inertia during mo-tor start-up can cause lengthened acceleration times duringwhich rotor ventilation is reduced. This can cause rotor dam-age or can lead to shortened rotor life.The temperature rating of the motor is shown on the mainnameplate as a temperature rise above an ambient tempera-ture. If there is a service factor, it is also shown. If the motortemperature switch opens, an investigation should be madebefore further operation is attempted.If the motor is of TEWAC (Totally Enclosed Water-to-AirCooled) design, the maximum inlet water temperature andthe water flow rate (GPM) at the air cooler must be as shownby the certified drawing. Otherwise, the discharge air tem-perature from the cooler (actually the ambient air for the mo-tor as shown by the main nameplate) could be too high forthe motor to properly cool.Check Rotation (Hermetic Motor)1. Engage the main motor disconnect on the front of the starterpanel. The motor is now ready for rotation check.2. After the default screen Status message states ‘‘Readyfor Start’’ press the LOCAL softkey; start-up checkswill be made by the control.3. When the starter is energized and the motor begins to turnover, check for clockwise rotation (Fig. 30).IF ROTATION IS PROPER, allow the compressor to comeup to speed.IF THE MOTOR ROTATION IS NOT CLOCKWISE (asviewed through the sight glass), reverse any 2 of the 3 in-coming power leads to the starter and recheck rotation.NOTE: Starters may also have phase protection and will notallow a start if the phase is not correct. Instead, aStarter Fault message will occur if this happens.Do not check motor rotation during coastdown. Rota-tion may have reversed during equalization of vesselpressures.Check Oil Pressure and Compressor Stop1. When the motor is up to full speed, note the differentialoil pressure reading on the LID default screen. It shouldbe between 18 and 30 psid (124 to 206 kPad).2. Press the Stop button and listen for any unusual soundsfrom the compressor as it coasts to a stop.59