The flameproof and intrinsically safe vacuum electromagnetic starter for mining is mainly used in the mine with gas and coal dust with explosion hazard, and is applied for start, stop and commutation at stop of three-phase squirrel-cage asynchronous motor with AC 50Hz, voltage to 1140V (660V) and current to 400A and below and of long-term working system and interrupted working system.
For main technical parameters, see Table 1.
Table 1
Model |
Rated operating voltage V |
Rated operating current A |
Rated frequency of the power supply Hz |
Working system |
QJZ-400/1140(660) |
1140 (660) |
400 |
50 |
Long-term |
5.2 Technical performance:
5.2.1 The starter insulation can withstand AC 50Hz, and there is no breakdown or flashover at the test voltage (effective value) specified in Table 2 for 1min
Table 2
Rated insulation voltage Ui |
Test voltage V |
≤60V |
1000 |
1140(660)V |
4200 |
5.2.2 For connecting and make-break capability of the main circuit, see Table 3
Table 3
Use Category |
Rated operating Current (A) |
Connecting connection |
Make-break condition |
Power on Time (S) |
Interval Time (S) |
Operation cycle frequency |
||||
I/Ie |
U/Ue |
cosφ |
I/Ie |
U/Ue |
cosφ |
|||||
AC-3 |
400 |
8 |
1.1 |
0.35 |
6 |
1.1 |
0.35 |
0.05 |
240 |
50 |
AC-4 |
400 |
10 |
1.1 |
0.35 |
8 |
1.1 |
0.35 |
0.05 |
240 |
50 |
AC-3: used for break at start and during operation of the cage-type synchronous motor AC-4: used for start, reverse operation and jog of the cage-type induction motor |
5.2.3 For overload protection, see Table 4
Table 4
Actual current / setting current |
Action time t |
Resetting mode |
Initial state |
Resetting time t |
1.05 |
No action for a long term |
-- |
Cold condition |
-- |
1.2 |
5min<t<20min |
Automatic |
Hot condition |
1min<t<3min |
1.5 |
1min<t<3min |
Automatic |
Hot condition |
|
6 |
8S≤t≤16S |
Automatic |
Cold condition |
5.2.4 See Table 5 for short circuit protection
Table 5
Actual current / setting current |
Action time |
Resetting mode |
8 to 10 times |
0.2S<t<0.4S |
Manual |
5.2.5 See Table 6 for phase failure and unbalance protection
Table 6
Overcurrent / setting current |
Action time |
Initial state |
|
Any two phases |
Third phase |
||
1.0 |
0.9 |
No action |
Cold condition |
1.05 |
0 |
<3min |
Hot condition |
5.2.6 See Table 7 for the electric leakage locking function
Table 7
Operating voltage of the main circuit (V) |
Locking action value (KΩ) |
Unlocking action value (KΩ) |
Allowable error |
660 |
22 |
≥1.5 times of locking value |
+20% |
1140 |
40 |
The translation quick door opening structure is adopted for the starter, it has the push-pull structure and has the built-in guide rail, so as to facilitate to pull out the body.
The control element is independently installed on a panel for quick replacement. ZKJB-K1 Chinese intelligent integrated protector is adopted as the control unit in the core protection part.
It has the functions of electric leakage locking, overload protection, short circuit protection, phase loss protection, under-voltage protection, overvoltage protection, program control and so on.
3. The full Chinese LCD display is adopted for the starter, which can display multiple parameters of the starter, such as the starter setting parameters, insulation resistance value,
operating current value, operating voltage value, work and fault type, failure parameters and so on. The maximum advantage is that the current value is continuously adjustable between 0-400 (315,
200)A.
It can be accurate to ampere, and the resolution is 1A. In case of overcurrent, short circuit, electric leakage locking, under-voltage, phase loss
program control failure and so on, it can automatically cut off power supply circuit, and display and memorize the failure type and failure parameters. Meanwhile, the starter is locked,
and the related failure text information is provided. It can be reclosed for power transmission after troubleshooting and manual resetting.
1 Structural feature
The starter consists of two parts of explosion-proof shell and vacuum body, and the vacuum body is installed in the explosion-proof shell.
(1) The starter consists of the rectangular explosion-proof shell on the base, there is wiring chamber above the shell and main chamber below, which are the independent explosion-proof parts. The starter has the quick-open structure, and the front door is the plane rabbet type. There is a rotation handle at the front left side. Lift the handle to horizontally rotate it by about 90°. Rotate it to the right side to open the door and to te left side to close the door. The interlocking lever is arranged at the front right, and there are two buttons at the right: start and stop; there is also a handle which isolates the commutation switch, two gears in total: power on and power off. Rotate the handle to the stop position, and rotate the interlocking lever to the locating slot to open the door. There is a window above the door cover, and there are three buttons below; confirm, up and down. The switch can be set.
(2) All elements of the vacuum body are installed on the bottom plate, and the front is installed with the vacuum contactor, motor integrated protector, remote and proximity switch, intermediate relay and fuse, so as to facilitate inspection, adjustment and repair. The back is installed with the conversion isolating switch, control transformer and start-stop button.
2 Working principle
2.1 Connect the commutation switch HGK, and the control transformer secondary output voltage, the normally on contact of the relay in the protector is closed, so as to make preparation for power supply.
2.2 Press the start button QA, and the intermediate relay ZJ coil is powered. The normally on contact is closed, and the coil of the vacuum contactor is powered on, so that the main contact is engaged for start.
2.3 Press the stop button TA, the intermediate relay ZJ is powered off, the normally on contact is disconnected, and the vacuum contactor coil is powered off, so that the main contact is separated to stop the motor.
2.4 In case of overload, short circuit, phase failure and other failures of the motor during operation, the normally on contact of the relay in the protector is disconnected, the intermediate relay ZJ is powered off, and CKJ coil is powered off and trips, so as to play the role in protection.
2.5 Before the starter is started, the electric leakage detection circuit of the protector conduct leakage detection of the load through the locking cable and ZJ and CKJ normally off contacts. When the grounding insulation resistance of the main circuit is lower than the specified value, it is locked. (1140V, the phase-to-ground insulation resistance is 40+20%KΩ; 660V, the phase-to-ground insulation resistance is 20+20%KΩ).
2.6 The body is arranged with the remote and close control switches. For example, if long-distance control is required, pull the remote and close control switches to remote control, the body is automatically started, and the button does not work. Pull the switch to close control for close control.
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