Trane CVGF Momentary Power Loss and, Current Overload Protection, Surge Detection Protection

Standard

Controls Protections

Momentary Power Loss and

Distribution Fault Protection Three-phase momentary power loss (MPL) detection gives the chiller improved performance through many different power anomalies. MPLs of 2.5 cycles or longer will be detected and cause the unit to shut down. The unit will be disconnected from the line within 6 line cycles of detection. If enabled, MPL protection will be active any time the compressor is running. MPL is not active on reduced-voltage starters from the initial start signal through transition. The MPL diagnostic is an automatic reset diagnostic. MPL protection can be disabled inTechView.

An MPL has occurred when the motor no longer consumes power. An MPL may be caused by any drop or sag in the voltage that results in a change in the direction of power flow. Different operating conditions, motor loads, motor size, inlet guide vane (IGV) position, etc. may result in different levels at which this may occur. It is difficult to define an exact voltage sag or voltage level at which a particular motor will no longer consume power, but we are able to make some general statements concerning MPL protection:

The chiller will remain running under the following conditions:

•Line-voltage sag of 1.5 line cycles or less for any voltage magnitude sag

•Control-voltage sags of less than 3 line cycles for any magnitude sag

•Control-voltage sags of 40 percent or less for any amount of time

•Second-order or lower harmonic content on the line

The chiller may shut down under the following conditions:

•Line-voltage sags of 1.5 or more line cycles for voltage dips of 30 percent or more

•Control-voltage sags of 3 or more line cycles for voltage dips of 40 percent or more

•Third-order or higher harmonic content on the line

Current Overload Protection

The control panel will monitor the current drawn by each line of the motor and shut the chiller off when the highest of the three line currents exceeds the trip curve. A manual reset diagnostic describing the failure will be displayed. The current overload protection does not prohibit the chiller from reaching its full-load amperage.

The chiller protects itself from damage due to current overload during starting and running modes, but is allowed to reach full-load amps.

High Motor-Winding Temperature Protection

This function monitors the motor temperature and terminates chiller operation when the temperature is excessive. The controller monitors each of the three winding-temperature sensors any time the controller is powered up, and displays each of the temperatures at the service menu. Immediately prior to start, and while running, the controller will generate a latching diagnostic if the winding temperature exceeds 265 ± 5°F (129.4 ± 2.8°C).

Surge Detection Protection

Surge detection is based on current fluctuations in one of three phases. The default detection criterion is two occurrences of RMS current change of 30 percent within 0.8 seconds in 60 + 10 percent seconds. With theTracer chiller controller, the detection criterion is adjustable.

Overvoltage and Undervoltage Protection

The unit will be shut down with an automatic reset if the line voltage is below or above 10 percent of nominal.

Must trip = 15 percent of nominal.

Time to trip = minimum of 1 minute, 10 seconds and maximum of 5 minutes, 20 seconds. Overvoltage and undervoltage protection can be disabled using TechView.

Power Factor and kW Measurement Three-phase measurement of kW and unadjusted power factor yields higher accuracy during power imbalance conditions than with CH530.

Short-Cycling Protection Short-cycling protection is based on a start-to-start time. This method uses a straight start-to-start timer to determine when to allow the next start.

A’Restart Inhibit Start-to-StartTime’ setpoint is used to set the desired start- to-start time. There is no ’free’ start on a power up at DynaView.The real-time clock is used to determine when the next start will be allowed, based on the previous start.

When the start is inhibited by the restart-inhibit function, the time remaining is displayed along with the restart-inhibit mode.

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