Basic electrical wiring of MVC series soft starter

2022-09-23
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The basic electrical wiring of MVC series soft starter of motor

(I) installation of main circuit

the standard MVC plus power wiring should connect the power directly to the input end of the main disconnector (see the figure), and the motor M should be connected to the terminals marked T1, T2, T3 in the control cabinet. It is recommended to use non gap arrester, which should be installed on the nearest pole

figure MVC series high voltage soft starter main structure diagram

the power line should be tightened according to the bolt size and torque table

the installation torque of the power line is shown in the table

meter power line installation torque table

bolt size torque (FT lbs) bolt size torque (FT lbs) 1/4 ~ 2069/16 ~ 12683/16 ~ 18125/8 ~ 11903/8 ~ 16183/4 ~ 101507/16 ~ 14307/8 ~ 92401/2 ~ 13451.0 ~ 8245 (II) wiring of control circuit and TCB circuit board

there is a risk of electric shock when installing or operating this part with electricity, so it is necessary to prevent injury. Do not touch the bypass electrical appliance or mechanical interlock, because it will cause equipment damage or fatal personal injury

c plus TCB circuit board

mvc plus TCB circuit board is used to connect digital controller (DCU) and user control logic. It is a 120V logic control board with many auxiliary contacts. The control contact has the function of time delay and emergency bypass protection. It can carry out sequence control, bypass contactor control and shutdown interlock control during starting. See figure

figure TCB circuit board diagram of MVC series soft starter

2 Start/stop control terminal block tb1

tb1 wiring diagram is shown in the figure. Tb1 wiring instructions:

(1) 1 and 9 are connected to 120V control power supply. If the manufacturer does not install this transformer, it is recommended to use a transformer greater than 750W. The complete MVC plus soft starters produced by motortronics are equipped with 120V control transformers. Note that this transformer can only be used as the control power supply of this machine instead of being used for other controls and other power supplies

figure tb1 wiring diagram

(2) and are factory jumpers, which are dry-type dynamic breaking contacts that can be used for user shutdown relay contacts after removing jumpers

(3) is a two-wire or three wire start/stop control terminal block. Among them, 6 and 8 are connected to the self holding contact of the dynamic closing relay, 6 and 7 are connected to the stop button, and 7 and 8 are connected to the start button

(4) are dry dynamic make and break contacts. It is synchronized with the start and stop, and can be controlled by other relay interlocking

figure TB2 wiring diagram

3 The wiring diagram of emergency bypass control terminal block tb2

tb2 is shown in the figure

(1) 1 and 2 are emergency bypass relay contacts. If a dry contact is used to close 1 and 2. This will cause the digital control unit to lose control and the display will not work. It will connect the bypass clutch to connect the motor directly to the input power supply

note: when the emergency bypass is used for starting, the electronic overload protection does not work. Take corresponding protective measures to ensure the safe operation of the motor

(2) is a C-type relay contact, and the initial state of this dry contact corresponds to the state of emergency bypass contacts 1 and 2. It is used to indicate the working state of emergency bypass

(3) is the user power supply 120V AC (400va), and 7 is the neutral line

(4) is a C-type switch, which is used for delayed start and stop control. The delay time is determined by x1, X2 and SW3 (see switch position and jumper selection in this section)

4. The wiring of interlocking/fault relay output terminal block tb3

tb3 is shown in the figure

and are C-type dry contacts, which act when the fuse is burnt out. And are C-type dry contacts. When a fault occurs, the relay contact will act

figure Tb3 wiring diagram

5 The wiring of time delay/power factor compensation terminal block tb4

tb4 is shown in the figure

the wiring diagram

and of figure tb4 are C-type dry contacts. When the motor reaches full speed, the auxiliary contacts act. X3, X4 and SW4 can determine the delay time (see switch position and jumper selection in this section). And are C-type dry contacts, which are contactors for PFC power factor regulation. When the motor reaches full speed, it acts. If users need it, they can change the delay time through X5, X6 and SW5 (see switch position and jumper selection in this section)

6. Terminal TB5

software is required for RS485 connection (if the wire distance is greater than 8m, appropriate resistance should be added)

7. Wiring terminal TB6

factory wiring is the wiring of power control board

8. Terminal tb7

factory wiring is the wiring of the power control board

9. Wiring terminal tb8

(1) factory wiring, but if the user purchases "only the soft start part" and does not include the power start clutch part, it should be wired by the user himself

(2) 1 and 2 are connected to dry fuse indicator and power clutch contact

(it is relatively simple to study the rapid iteration and development of tube assembly structure. 3) 3 and 4 connect the break contact to the overload detection element. If such wiring is required for emergency bypass operation

(4) 5 and 6 are connected to dry-type dynamic breaking contacts, which come from the bypass contactor node to indicate the full speed operation of the motor, and are connected by the factory

(5) 7 and 8 are connected to the coil of the contactor that has become one of the five provincial innovation centers in the province to indicate the connection and disconnection of the contactor, which is connected by the factory

(6 makes the tensile test result more accurate and reliable) 9 and 10 wiring input the control coil of the main contactor of the power supply to indicate the on-off of the power contactor, which is connected by the factory

note: the above all use dry contacts, and the maximum capacity of the contacts is 960va, 120VAC

b LED indicator on the power control board (Figure)

(1) -12v: DC power supply

(2) +12v: DC power supply

(3) start: the start command has been added to the TCB control board

(4) fault: there is a fault

(5) fuse blow: the disconnector is open or the fuse is burnt out

(6) PFC on= capacitor power factor compensator is switched on

(7) timed out= auxiliary time delay relay action

11. Jumper selection

the jumper diagram on the TCB board is shown in the figure

figure jumper diagram on TCB board

start delay: the selectable delay time from the time when the start command is sent to the time when the CPU actually receives the start signal. Select X1 or X2 to determine its delay method, which is calculated in cycles or seconds. Refer to SW3 and set the actual delay time

(1) x1= (dly-c) starting delay is in cycles

(2) x2= (dly-s) start delay is in seconds (factory set)

auxiliary delay: select X3 or X4 to determine the unit of delay after the bypass contactor is closed

(1) x3= (aux-c) auxiliary delay is in cycles

(2) x4= (aux-s) auxiliary delay is in seconds (factory set)

time delay of power factor compensation contactor. The time unit from the closing of bypass contactor to the change of state of compensation contactor is set by X5 and X6

(1) x5= (pfc-c) the action delay time of compensator is in cycles

(2) x6= (pfc-s) compensator action delay time is in seconds (factory set)

12. Switch setting position

see figure for switch position setting

for example, if the delay time of each bit is 2n-1s and the switch positions are set to 1, 2 and 3 as "on", the delay time is ++ = 1+2+4=7s

(1) sw1= not used

figure switch position diagram

(2) sw2* = on/off deceleration control (factory set to non deceleration off state). On refers to soft stop and deceleration shutdown of motor. Off is to allow the motor to slide and stop under the free running state

switches SW3, SW4 and SW5 are seven position switches, which can be used for binary coding of 127S or cycles at most

(3) SW3 startup delay is composed of 7 dual row switches, which can set the maximum binary count to 127, and each cycle represents one second. Refer to the route selection above (factory setting is 2S)

(4) the auxiliary delay when the SW4 motor reaches full speed is composed of seven dual row switches, and the maximum value of binary count can be set to 127, and each cycle corresponds to one second. See the jumper selection above (factory set to 3S)

(5) sw5** = PFC capacitor power factor compensator time delay, which is composed of seven dual column switches. The maximum binary count can be set to 127, and each cycle corresponds to one second. See the jumper selection above (factory set to 3S)

* soft stop must be set to effective

** in the cup setting, the time is attached to SP2

13. Grounding

(1) the grounding cable should be connected to the "GND" at the lower part of the main control panel

(2) three phase 120V refers to the power transformer from crack to crack, in which B is correspondingly connected to the cabinet ground wire

(3) check the resistance between all grounding wires with an ohmmeter

(4) the standard MVC plus series soft starter structure ground wire is always at the bottom of the cabinet, while the MVC plus ground wire for the "soft start only" part is located at the lower part of the main control panel

figure communication board

(III) communication board wiring

the description here is only applicable to soft starters configured with communication options, for reference only

1. Communication board

the diagram of communication board is shown in the figure

2. Communication board wiring

the communication board wiring diagram is shown in the figure

3. Cup power control board

cup power control board is shown in the figure

p board wiring terminal

cup board wiring terminal block wiring diagram is shown in figure

figure communication board wiring diagram

figure power board diagram

5 Wiring of power control board

wiring of power control board is shown in the figure

figure wiring diagram of power control board

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