The UPS uses the preheat cycle in order to warm the rotor. The preheat cycle is necessary to verify if preheat is necessary with the start of the flywheel. There are various factors that determine if preheating is required. The first factor is the armature temperature.
The armature temperature of the flywheel must be at least
- Entering the "Online" state and the flywheel temperature is below
30° C (86° F) - Prior to the calibration of the rotor position sensor and the flywheel temperature is below
30° C (86° F)
If the temperature is greater than
In a normal preheat cycle, the armature temperature determines the length of the preheat cycle. If the temperature is below
After the preheat cycle is completed, a time period of thermal equalization is determined. The time to equalize allows the heat that is generated in the armature to be radiated into the rotor. Thermal equalization allows temperatures to equalize. The minimum and maximum times for equalization are 6 minutes and 15 minutes. The time for the equalization of the temperatures will be equal to the preheat time. The time period for thermal equalization will not be greater than 15 minutes.
Once the preheat cycle is complete, the UPS will automatically continue with start-up or the calibration of the Rotor Position Sensor.
A 42 minute preheat cycle for the flywheels will be initiated if the power to the flywheel cabinets has been turned off for more than 48 hours. In some cases, the preheat length will not be needed and will overheat the armature if completed. The overheating will result in a delay in order to obtain nominal rotor speed. Call technical support in order to receive a password to force a non-standard preheat in place of the 42 minute preheat mode.
The technical support representative will ask three questions in order to determine if the preheat time can be shortened. The following statements will pertain to the questions that will be asked by the representative:
- The temperature in the room of the flywheel
- The length of time of the flywheel in the room in this temperature
- The length of time since the energizing of the flywheel (full speed)
If a certain condition exists, technical support can issue a preheat password in order to force a non-standard preheat. The computer that is being used must be connected via a direct serial connection. A "Control F" is required to retrieve the MMU serial number and seed number for pass code generation. Type "Ctrl-^" in order to issue the override command into the UPS.