Multifunctional protection device UZM - connection diagram and principle of operation

An ultrasound scanner or multifunction protection device is designed to provide instant disconnection of network equipment, provided that there is a certain increase or decrease in voltage in the single-phase network from which this equipment is powered. Thus, the equipment of an apartment, garage, office, home, etc. is protected from the harmful effects of short-term power surges.

These jumps can be caused by factors such as the inclusion of electric motors, electromagnets, magnetic starters, powerful devices, etc. fed from the same network. A quick shutdown by means of an ultrasound device prevents equipment failure and can prevent a possible fire and, in some cases, even a fire .

Being connected according to this scheme, the ultrasound can serve pulse relay. If the neutral conductor breaks, the load is immediately turned off, and when the neutral conductor is connected again, the ultrasound transformer will turn on the load after it has withstood the time delay set by the user.

In addition, USM can be used to limit the inrush current at the time of connecting a capacitive load to the network. The current limitation in this case is achieved by the fact that the relay contacts close exactly at the moment the mains voltage passes through zero, that is, switching is carried out in soft mode at zero current.

UZM-51M and UZM-50M devices are powerful voltage monitoring relays. At the outputs of these devices are placed quite powerful electromagnetic relays. In addition, there is also protection on varistors. Installation of these devices is carried out to 35 mm DIN rail.

The supply wires of the switched circuits are connected at the front. Tunnel terminals provide reliable clamping of wires with a total cross section of up to 35 sq. Mm.

There are two indicators on the front of the USM, one of which is green / red (two-color), which signals the status “normal” or “accident”, and the second is yellow, indicating that the relay contact is on.

Also on the front panel there is a button for manually turning on and off the ON / OFF. On the model UZM-51M there are special knobs for adjusting the lower and upper voltage thresholds.

The whole structure of the ultrasound scanner is located on the printed circuit board. All the necessary electronic components, current shunt, relays and power buses are installed here. The board gives the product mechanical strength and a fairly high reliability.

The latest UZM models are equipped with larger terminals with windows 9 by 8.2 mm, as well as a locking screw with M6 thread. The protective flags on the terminals help to avoid mounting errors. The UZM-16 device, unlike the above, allows you to connect wires to it with a total cross section of up to 2.5 sq. Mm. Of course, ultrasound does not replace RCD, circuit breakers, SPD other.

UZM are applicable in networks with any configurations: TN-S, TN-C, TN-C-S, TT. When the mains voltage failure lasts less than 0.5 seconds, the device will not disconnect the load and will not create a delay for reconnection. But at the moment when the supply voltage is supplied, the device will first sustain a standby period of 5 seconds, the indication will not turn on, and after 5 seconds the green indicator will blink - this indicates that the pre-exposure countdown is in progress.

While the voltage is within acceptable limits, the load is connected to the mains, while the yellow and green indicators light up. You can speed up the load connection manually by pressing the ON / OFF button.

If an emergency shutdown occurs, the relay will turn on automatically after 10 seconds as soon as the voltage returns to normal.If in the emergency mode, you try to turn on the device with the ON / OFF button, the USM will not allow power to the load.

In normal mode, the device will continuously monitor the supply voltage. If high-voltage pulses occur in the network, then the varistor protection built into the ultrasound transducer shunts these jumps to a safe value.

The operation of the two-color display depends on the current mode. When the mains voltage approaches the upper cut-off threshold, the red indicator starts flashing, but as soon as the voltage exceeds the permissible limit, the load will automatically disconnect, the red indicator will light continuously, and the yellow one will turn off.

From the moment the voltage has returned to acceptable limits, the countdown starts until it is switched back on, and the green indicator flashes (if the voltage again falls outside the permissible range during the countdown, the countdown resets). When the countdown is over, the load will be reconnected to the mains.

When the mains voltage approaches the lower threshold, the green indicator starts flashing, and as soon as the voltage goes beyond the lower limit, the shutdown delay countdown starts and the red indicator starts flashing. As soon as the countdown has ended, if the voltage has not returned to normal, the load is switched off, the yellow indicator goes out, and the red one will now light up every 2 seconds.

If the voltage returns to normal, the start delay countdown starts, the green indicator starts flashing (if the voltage goes outside the limits again, the countdown starts again), and at the end of the count, the load will be connected to the mains again.

When manually disconnecting the load (using the ON / OFF button), the two-color indicator will reflect this by alternately flashing green and red. To return to normal operation, press the ON / OFF button repeatedly.

When the load is turned off by the ON / OFF button, the device will remain off even after disconnecting and then turning on the power again. To turn on the relay in this case, you must press and hold the ON / OFF button again for 2 seconds.

To change the time delay to re-enable (10 seconds or 6 minutes), first open the relay with the ON / OFF button.

Then press and hold ON / OFF, the “norm-alarm” indicator goes out, but after a while it starts to flash. Flashing green indicates that the delay time is set to 10 seconds, and if it is red, the delay will be 6 minutes. After that, the ON / OFF button can be released.

Pressing ON / OFF again will put the device into normal operating mode, the relay will be turned on. When the device opens the circuit, the circuit always opens in phase. The neutral wire is connected through for easy installation. It always connects on one side only.