Product information | Optimum functions for HVAC

Optimum functions for HVAC
Operation is continued even after the momentary power failure thanks to the auto-restart function.

Even if a momentary power failure occurs, load inertia of a fan or blower, etc. is used to maintain the motor's operation while the motor's operating speed gradually drops, and enables the motor to restart operation without stopping.
(The motor may stop on occasion due to the load's inertial moment.)

A pick-up function provides smooth starts.

If you desire to run a fan which the inverter is not currently running and which is turning free, this function will pick up on its motion regardless of the direction it is turning in and start it operating. Momentary switching is performed in the inverter from the commercial power supply and provides a convenient function when starting motors, etc.

Tripless operation through regenerated current avoidance control

Deceleration time is controlled to match the internal energy level generated in the inverter, and so deceleration and stopping is accomplished without tripping due to overload.

Even greater energy savings through the low water volume stop function

When there is pump operation accompanying "pressure drop" that occurs due to pressure loss or leakage, etc. in the piping, etc., or at times when the pump runs repeatedly to obtain a small volume of water, this function controls the pump's operation, preventing it from being driven with the water volume below a predetermined level, and thus reducing wasteful pump operation and saving even more energy.

The equipment's operating condition is determined by the low torque detection function.

The inverter determines the load state of the connected motor and if it drops below a predetermined level, it judges that a "Low Torque" state exists and outputs a signal to that effect. In this way, any trouble that occurs in the equipment (such as a belt on a pulley breaking) can be grasped by the inverter.

Also avoids operation signal trouble through the command loss detection function.

If the frequency signals (0 to 10V, 4 to 20mA, multi-step speed operation signals, communications, etc.) that are connected to the inverter are blocked, signals are output as a "command loss," indicating that a frequency command was lost. In addition, output frequency when the command loss occurred can be set in advance, so even if a frequency signal line to equipment is broken due to machine vibration, etc., machine operation can be continued uninterruptedly.

Simple circuit configuration using the commercial line switching sequence

Inverters are equipped with the commercial line start function that enables switching between the commercial line and the inverter by an external sequence. In addition, inverters are equipped with two types of built-in sequence for operation with commercial line; i.e., Fuji's standard sequence and the automatic switching sequence to the commercial line activated when the inverter alarm occurs.
Note: The latter sequence differs from the one for forcible switching to the commercial line during inverter breakdown.

Continuous equipment operation through overload avoidance control

If the load on a fan or pulley increases due some foreign object getting wrapped around the shaft, etc., and the inverter's internal temperature rises suddenly or the ambient temperature rises to an abnormal level, etc., causing an inverter overload state, the motor's speed is lowered, reducing the load and enabling operation to continue.

Inverters are equipped with full PID control functions.

Low water level stop function, deviation alarm and absolute value alarm outputs have been added to the PID regulator which performs such tasks as temperature, pressure and flow rate control. In addition, an anti-reset windup function that prevents PID control overshoot as well as a PID output limiter and integral hold/reset signal provide easy-to-adjust PID control functions.

Simple Sequences through Universal DI/DO

Signals can be transmitted to a higher level controller or PC by connecting digital signals to an inverter from different types of sensors, such as a float switch used to judge the level in a water storage tank, which serve as peripheral devices to the inverter. In the case of small-scale equipment, even if a programmable logic controller (PLC) is not used, information can be sent to a higher-level system easily.

Elimination of display devices by use of the analog input monitor

Using the display coefficient of signals from devices such as flow rate or temperature sensors in air conditioning equipment, these signals can be converted into physical values such as temperature and pressure and displayed synthetically on the inverter's keypad without making the use of exclusive flow meters or air flow meters.

Improved capability for handling regenerated energy

When the inverter slows down and stops the motor, if the braking energy regenerated by the motor exceeds the braking capacity of the inverter's main circuit capacitor, the inverter will trip. At such a time, if even a little excess energy trips the inverter, using this function you may be able to absorb the excess braking energy without connecting to a braking resistor.

Other convenient functions

- Motor condensation prevention function
Prevents condensation of the motor from occurring in cases where the surrounding temperature changes suddenly while the motor is stopped.

- Motor speed display with percent
The inverter's keypad displays the operating frequency (Hz) or the motor's rotational speed (r/min), but it can also display the maximum speed as 100%, so it is easy to get a grasp of the equipment's operating state.