A series of alarm input modules of reserve MAVR-3 is designed to operate in four-wire networks of 230/400V with isolated zeros

Automatic transfer switch controller unit (MAVR-3-1)
MAVR-3-1 UHL4 13600.00 руб. с НДС

The simpliest three-phase automatic transfer unit (AVR) or how to connect a MAVR-3-1 control module

 Three-phase power supply systems for a 0,4 kV voltage are the primary distribution systems of most final customers. A connection of consumers with various load characteristics to one electrical power supply line causes an occurrence of modes which are called abnormal (alarm) ones. These modes include short-circuit, not full phase power supply, synchronous oscillation or reducing the frequency and other factors which disturb a normal electrical power supply. These factors required of two supply directions of energy saving:
- Firstly, carrying out calculations of transitive (electromagnetic) processes associated with short circuits, and other (electromechanical) processes associated with a stability, synchronous oscilatoins and an asynchronous operation.
- Second, a development of relay protection and automation for consumer networks.
 Protection devices allow to monitor for electric nets of power supply energe saving systems. A protection of consumer nets by using automatic devices is means to raise a switching speed, changing electrical receiver modes with an active and reactive takeoff power. The main purpose of relay protection devices is to prevent a development of net alarms and the equipment failures, to localise alarm sections, and to input necessary  reserve. All these operations shall be performed by automatic devices without any assistance of operation personnel. Personnel assistance will be required at the second stage, to restore a normal power supply operation, to clear problerms in lines and an electric equipment. At the first stage of a failure escalation a human can not react to an alarm situation, has no possibility within a short time (a fraction of a second) to estimate a situation, to make a decision and to perform necessary actions.
 In automatic protection systems the most widely used devices of automatically transfer switch control units and re-enable devices.
 Application of module automatic input of reserve MAVR-3-1
 The module automatic input reserve MAVR-3-1 (the module) is a control device is designed to automatically switch to reserve line at disconnected or a fault of operating line. The device is designed for operation in the cupboards (units) of control the automatic enabling a reserve power in systems uninterruptible power supply 3-phase electrical receivers of I and II category of connection according to the SAE requirements.
 The module monitors the voltage on the main and reserve inputs 3-phase net. If the voltage is within the normal, load is powered from the input with the priority (default it is input 1).
 Load connection provides a switching device (KM) of the electromagnetic type, the contactor or starter. KM is controlled by the relay output to which is fed operative supply. Load capacity of the relay output (AC1 AC250V 16A). In an alarm on the main input is done off the load from the main input and switch to the reserve input. When power is restored to the main input, load is automatically transferred from reserve at the main input, when installed link priority. Technical characteristics of the device are shown in Table 2. Circuit connection is shown in Figure 3.
Functional capabilities
 Module MAVR-3-1 is a ready-to-use device consisting of three independent electronic modules: two modules of contorl parameters of the three-phase four-wire net with neutral (voltage control relay) and microprocessor unit. Relay of control voltage of each input has an LED indication of duration state of the net. Power of modules is carried out from controlled net. Relay of control voltage are galvanically by separated each other and by microprocessor unit.
 The microprocessor unit analyzes the readiness of main and reserve inputs, and the current state of the digital inputs, and then issues the control signals in the form of dry contacts. Power of microprocessor unit is carried out from phase L1 of the first and second inputs. Operative power is generated from phase L1 of the first input or phase L1 of the second input. In the absence of two phases, the microprocessor unit is not able to perform its function.
 Module MAVR-3-1 provides:
- control of phase alternation and voltage values at the input 1 and input 2;
- control of break or lowering the voltage below the threshold for any of the phases on the input 1 or input 2;
- supplying operative voltage to power of KM (the switching mechanism of the electromagnetic type, the contactor or starter)
- alarm indication and the ability to connect external alarm devices via the built-in relay;
- enable or disable a priority on input 1 or input 2;
- key lock on the front panel, the ability to connect an external control using the service jack;
- setting thresholds of disabling input 1 and input 2 on the voltage values Umin, Vmax;
- setting of enable, disable, re-enable input 1 or input 2 with priority and without input priority.
 On the front panel there are mnemonic circuit, LED indicators of the phase voltages, the indicators of threshold values Umin and Umax, KM indicators, alarm LED, buttons of device control (see Figure 1).
 The device is designed for shield mounting. Case material - plastic ABC. Mounting the device is carried into the mounting hole dimensions 136*136 mm. Two brackets are used for fixing, which are included in the delivery.
 On the patch panel (Figure 2) is placed two fuses for each input, jacks to connect input 1, input 2, KM1, KM2, external alarm device, DU, installation switches Umax, Umin separately for each input, switches Timeon Timeoff, Timerestart, unit of microswitches "modes."
 Buttons "Input1", "input2", "Auto" are designed for local control device: switching on or switching inputs, enable automatic control mode (LED indicator). Button Stop - disable KM1 and KM2.
Front panel of MAVR-3-1
Figure 1
Figure 2
Responsive elements of jacks to connecting the patch panel are mounted on a patch panel.
 Operation of the module
 The device must be connected as in Figure 3 according to the rules and standards of electrical safety. Works related to the installation, wiring and testing must be carried out by qualified specialists who have access to work with electrical equipment up to 1000V. Before starting work, make sure there is no voltage at the connection of the tires.
 When applying power to the unit for the first time, you must select the control mode: manual or automatic. To selection manual control must be pressed and hold the button "Input 1" and "Input 2". To automatic - press and hold the button "Auto". To disable the control click "Stop" is necessary.
 To jack "External Control", are connected buttons of remote control of unit  (see Figure 3). Alarm mode: In an alarm on the main input the module transfer the load to reserve input. When power is restored to the main input (if the priority is set), after the expiration of the recovery time, the module will transfer the load to the main input. In any alarm situation (module can not perform its function) is closed dry contact "Alarm" and will light up the LED "Alarm" on the front panel.
 Diagram of operating is shown at Figure 4.
If in case of an alarm on the first input (if does not set priority), with automatic switching to another input appears an alarm on the second input, the output relays K1 and K2 disable switching devices KM1 and KM2, is turned on an indicator "Alarm" and the indicators Input 1 and Input 2 will start flashing.
Figure 3
Figure 4
 Diagram of operating of the device (Figure 4). Where: ton - time delay of turning on the relay; toff - time delay of turning off the relay; trestart - time delay of restart; t - time of momentary power interruption.
 After powering on the device (set priority Input 1 "U1") is activated relay of input 1 "K1" with delay ton, power is supplied to the load.
 In an alarm on input 1 "U1", after the couting delay toff. activated relay of input 1 "K1" and occures a disconnection of load from input 1. Through time trestart  is turned on relay of input 2 "U2" - "K2" and the load is connected to the input 2 "U2".
 When power is restored to input 1 "U1", through time trestart is switching to input 1 "U1" (if is set priority of input 1).
 Time toff is set taking into account the the fact that, in the short-term failures of line at duration t <toff  will not switching line.
 Setup module
 To setup device, you must set the values Umin and Umax determining the operating voltage range for the input 1 and input 2. A setting the operating voltage should be made taking into account the characteristics of the equipment connecting to the switchgear (valid values Umin/Umax - see Table 2).
Enabling time is set from the calculation of the required speed of load connection and total switching time to a reserve line. off time is defined by the characteristics of the supply lines and the mode of operation of the equipment. Time off is defined by the characteristics of the supply lines and the mode of operation of the equipment. When voltage is instability on the receiver of switchgear (switchgear) and variable operation mode of the equipment the time off time should be set taking into account the in order to eliminate false alarm of automation. Restart time is provided for enabling a function of restore working line without disabling or switching a load on reserve. If time of restart does not expired, and alarm input is restored, that switching to reserve does not occur. If time of restart is expired, and alarm input does not restored, that switching to reserve is occures. Setup of device operation using unit of microswitches is shown in Table 1.
Determination of priority
Input 1
Input 2
Locking the controls on the front panel
Self-recovery in manual mode
Not used
Not used
Indication of alarm modes
 Indication of alarm operation modes is provided as for automatic mode of control line status, and for manual control of device. Indicators Input 1 and Input 2 enable to assess the state of each tire, the nominal voltage level on the input and readiness of line (input) to supply the load. In an alarm state of any input turns off the corresponding indicator. If the value of the acting voltage at the input is above or below the set threshold value is turned on an indicator increased (> U) or low (<U) voltage and alarm indicator. The line from which is produced power takeoff is controlled by indicators of buttons Input 1 or Input 2. Alarm LED turns on at any alarm situation (bus interruption, breach of alternation, lack of voltage, overvoltage, switching mode to reserve). Disabling alarm indicator occures automatically after self-recovery of line or after a successful switching on a reserve.
 Specification of MAVR-3-1  
A parameter
Type of controlled lines ( 3-phase, 4-wires)
L1, L2, L3, N
Quantity of controlled inputs
Supply voltage input1, input2
Frequency of net
Maximum switching voltage/at current
AC400 / 5*
Maximum current of load, AC1 /at voltage
16 / AC250*
Thresholds of turning off Input 1, Input 2 at Umax
243, 249, 255, 261,267, 273, 279, 285, 291, 297
Thresholds of turning off Input 1, Input 2 at Umin
217, 211, 205, 199, 193, 187, 181,
175, 169, 163
Delay of turning off
0.1, 0.5, 1, 2, 3, 5,10, 20, 30, 60
Delay of turning on
0.1, 0.5, 1, 2, 3, 5, 10, 20, 30, 60
Delay of restart
0,1s, 1s, 3s, 8s, 15s, 30s, 1min, 2min,
3min, 6min
Control of break phase
there is
Control of alternation phases
there is
Control of "stiking" phases
there is
Switching endurance
Operating temperature range
Storage temperature
Immunity to interference from bursts in accordance with GOST R 51317.4.4-99 (IEC/EN 61000-4-4)
level 3 (2kV/5kHz)
Immunity to interference over voltage in accordance with GOST R 51317.4.5-99 (IEC/EN 61000-4-5)
level 3 (2kV L1-L2)
Climatic modification and placement category by GOST 15150-69 (non-condensing)
The degree's protection at case/terminals according to by GOST 14254-96
IP54 / IP20
The degree of pollution in accordance with GOST 9920-89
Relative humidity of air
up to 80 (at 250C)
Height above sea level
до 2000
Operating position in space
round the clock
Brackets length
*- Necessarily using protection chains against switching emissions
Order code
File to download
File date


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