MT/T 661-2011General technical condition for electrical apparatus used underground mine (English PDF)

4.6 The rated frequency of electrical apparatus is generally 50 Hz.

4.7 Electrical apparatus is generally 8 h working system. The others are

regulated by their respective product standards.

4.8 Electrical apparatus shall be equipped with the necessary spare parts,

accessories, special tools and accompanied files. It shall be provided with two

sets of important electronic plug-in, or one set of general electronic plug-in, to

facilitate the use, management, maintenance of the user. The accompanied

files shall include the product certificate, instructions for use, packing list.

5.1 Conditions for normal use

Electrical apparatus shall work reliably under the following conditions.

a) The ambient air temperature is -5 °C ~ +40 °C1), the average temperature

within 24 h does not exceed 35 °C.

b) Altitude of the location of installation. The altitude of low-voltage electrical

apparatus does not exceed 2000 m 2 ). The altitude of high-voltage

electrical apparatus does not exceed 1000 m3).

c) Relative humidity of the surrounding air. The relative humidity of the air

does not exceed 50% at a maximum temperature of 40 °C. It allows a

higher relative humidity at a lower temperature, for example, 90% at 20 °C.

For the condensation that occasionally occurs due to temperature

changes, it shall take special measures.

d) The use in places where there is a risk of gas and coal dust explosion

shall follow the provisions of clause 4.3.

e) In a non-corrosive, non-insulation-destructive gas or vapor environment.

f) In places where there is no significant vibration or shock.

g) In places where dripping and liquid intrusion are prevented.

h) The grade of contamination is grade 3.

5.2 Requirements for structure and explosion-proof

1 For the use of electrical apparatus when the ambient air temperature is above +40 °C or below -5 °C,

refer to the notes to clause 6.1.1 of GB 14048.1-2006.

2 For the low-voltage electrical apparatus which is installed at an altitude of more than 2000 m, refer to

the provisions of note 6.1.2 of GB 14048.1-2006.

3 For the high-voltage electrical apparatus which is installed at an altitude higher than 1000 m, follow the

provisions of clause 2.2.1 of GB/T 11022-1999 to convert the relevant parameters.

5.2.5 Markings, interlocks and warning labels

5.2.5.1 On the obvious parts of the enclosure of electrical apparatus, it shall

provide a clear and durable marking. The marking for the explosion-proof

electrical apparatus shall comply with the provisions of clause 27 of GB 3836.1-

5.2.5.2 The interlocking device of electrical apparatus shall comply with the

provisions of clause 10 of GB 3836.1-2000.

5.2.5.3 For the electrical apparatus that generates sparks or arcs during normal

operation, its enclosure which uses the quick-acting door cover shall be

provided with an interlocking device. When the power is turned on, the

enclosure's door cannot be opened; when the enclosure's door cover is opened,

the power cannot be turned on. The door cover which is fixed by the use of bolts

is allowed to use the warning label, on which it shall indicate the words "It is

forbidden to open the cover with power".

5.2.5.4 For the electrical apparatus which has a DC voltage higher than 60 V

and the AC voltage higher than 36 V, if the live part may be accessed after

opening the cover or removing the apparatus's parts, it shall provide the

protective cover which has a degree of protection not less than IP20, as well as

the warning labels of "Beware of electric shock" or "Electricity".

5.2.5.5 For the structures which are interlocked by the use of isolation switch, it

shall be clearly visible at the opening position of the contact, or otherwise it shall

be able to correctly judge the contact's status through the position of handle.

5.2.5.6 For the enclosure of electrical apparatus with built-in capacitors, heat

elements and quick-acting door or cover structure, the time interval from power-

off to opening of cover shall comply with the provisions on the allowable time

for opening the door or cover of enclosure in GB 3836.1-2000. It shall provide

the warning label on the time interval. The time interval shall be as specified by

the product standards.

5.2.6 Structures of cable and conduit entry device

The cable and conduit entry device shall be selected according to different

structural types. The common type for mining use shall comply with the

provisions on the cable entry device of GB/T 12173. The cable and conduit

entry device of explosion-proof type (except for intrinsic safety type) shall

comply with the provisions of clause 16 of GB 3836.1-2000. The introduction

and connection of flameproof cables and conductors shall also comply with the

provisions of clause 12 of GB 3836.2-2000.

5.2.7 Electrical clearance and creepage distance

Flameproof electrical apparatus for mining use shall comply with the relevant

provisions of GB 3836.1-2000, in addition to the provisions of GB 3836.2-2000.

5.2.12 Increased safety electrical apparatus for mining use

The electrical apparatus which is used in the shaft station of underground coal

mine, trunk intake airway, main intake airway, and other places (see Table 1)

may be of increased safety type. The marking is "Exe I".

The increased safety electrical apparatus for mining use shall, in addition to

complying with the provisions of GB 3836.3, also comply with the relevant

provisions of GB 3836.1-2000.

5.2.13 Intrinsic safe electrical apparatus for mining use

Electrical apparatus which is used in underground coal mine where there is gas

or coal dust explosion hazard may be of intrinsic safe type. The marking is "Exib

I" or "Exia I".

The intrinsic safe electrical apparatus as well as its related equipment shall, in

addition to complying with the provisions of GB 3836.4, also comply with the

relevant provisions of GB 3836.1-2000.

5.2.14 Composite type electrical equipment

If more than one explosion-proof types are used on an electrical apparatus, it

shall first indicate the markings of the primary explosion-proof type, followed by

the markings of the other explosion-proof types. The method of marking is as

shown in the relevant provisions of GB 3836.1-2000. For example, the

explosion-proof marking for the flameproof-and-intrinsic-safe combined

electrical apparatus is "Exd[ib] I".

The composite type electrical apparatus shall, in addition to the special

standards for the relevant explosion-proof type, also comply with the provisions

of GB 3836.1-2000.

5.2.15 Graphic symbol of electrical schematic diagram

Electrical apparatus's enclosure shall generally have electrical schematic

diagrams or wiring diagram label. The graphic symbols and wiring numbers as

indicated in the drawings shall comply with the provisions of such standards as

GB/T 4026, GB/T 4728, GB/T 5094.1, GB/T 7159.

5.2.16 Color of conductors

5.2.16.1 If the busbar of the main circuit and the insulation conductors of the

electrical apparatus are marked by color, it may make reference to the

provisions of Table 5. Meanwhile it shall also consider its mechanical strength

5.6, 5.7, 5.8 of GB/T 11022-1999. It shall also meet the following requirements.

For the control devices such as low-voltage starters and contactors, when using

electromagnetic operation, within the range of ambient air temperature -5 °C ~

+40 °C, at the control power supply's voltage within the range of 75% ~ 110%

of the rated voltage (Us), or within the range of 85% ~ 110%, it shall pull-in

reliably. At this time, the value of 75 % or 85% indicates the lower limit of the

pull-in action voltage, whilst the value of 110% shall be the upper limit. This

action range is applicable to AC and DC.

Note. Whether the fluctuation range of the control power supply's voltage is 75%

~ 110%, or 85% ~ 110% is determined by the product standard or the

manufacturer.

The release voltage during electromagnetic operation shall not be higher than

60% of the rated control power supply's voltage (Us). The release voltage shall

not be less than 20%Us for AC frequency; it shall not be lower than 10%Us for

DC.

For the high-voltage contactors, starters and other control apparatus, when

using electromagnetic operation, within the range of ambient air temperature -

5.3.2 Temperature-rise

The temperature-rise of such parts as the wiring terminals, accessible parts,

main circuits, control circuits, auxiliary circuits of such control appliances as

low-voltage starters, contactors, feed switches, etc. shall comply with the

provisions on temperature-rise in GB 14048.1-2006, GB 14048.2, GB 14048.4-

interlocks and/or electrical interlocks which are installed under normal status

shall be used.

5.3.4.4 Dual-speed starter

The switch-on and switch-off capability of the dual-speed starter is same as that

of the common starter. The product shall have the automatic or manual

switchover device or function from low-speed to high-speed. The switching can

be based on the time principle and current principle. The switching time and

current are as specified by the product standard or by the user and the

manufacturer through negotiation.

5.3.4.5 Overload current withstanding capability

For the contactors which use the category AC-3, AC-4, the overload current

withstanding capability of the starter shall comply with the requirements for the

overload current withstanding capability in GB 14048.4-2003.

5.3.4.6 Agreed operational performance

The low-voltage switchgear shall comply with the provisions of the agreed

operational performance in GB 14048.1-2006;

The high-voltage switchgear shall comply with the relevant provisions on

mechanical operational performance of the isolating appliance in GB 1984, GB

1985, GB/T 11022-1999, as well as the supplementary provisions as follows.

Operational control power supply's voltage for the agreed operational

performance of contactors and starters follows the operating conditions as

specified in this standard. The switch-on and switch-off conditions for the

operation of different categories of use shall comply with the provisions of the

agreed operational performance in GB 14048.4-2003.

5.3.4.7 Mechanical life (mechanical durability)

The mechanical life of low-voltage switchgear shall comply with the provisions

of GB 14048.1-2006, GB 14048.2, GB 14048.3, GB 14048.4-2003. The number

of mechanical life test is recommended as.

0.1, 0.3, 1, 3, 6, 10, 30, 100 (10000 times).

It is specifically specified by product standards.

The mechanical life of high-voltage switchgear shall meet the requirements of

mechanical life clauses in GB 1984, GB 1985, GB/T 11022-1999, JB 8739.

5.3.4.8 Electrical life (electrical durability)

voltage distribution device adopts the protection principle of power direction

type, current type or current direction type, the action parameters of the single-

phase grounding protection device are specified as follows.

- The primary lowest starting current of zero sequence current transformer I0

= 0.5 A; the maximum setting current I0 = 6 A;

- The minimum starting voltage of the opening voltage of the open delta of

the voltage transformer U0 = 3 V; the maximum setting voltage U0 = 25 V.

The leakage resistance shall reliably act at 1 kohm. The U0 action value is

recommended not to exceed 10 V. The recommended maximum value of the

setting current Ie is not more than 2 A, to improve the sensitivity of the leakage

protection device. The action time of the protection device itself is <= 100 ms.

In addition to the above protection, the rest is as specified by product standards.

Note. According to the need, the user negotiates with the manufacturer to

determine what kind of protection is set. The specific technical parameters of

the above protection are as specified by the product standard according to the

relevant standards, in addition to the provisions of GB 14048.4-2003 and this

standard.

5.3.8 Requirements for electromagnetic compatibility (EMC)

Unless otherwise specified in the product standards, the electromagnetic

compatibility of electrical apparatus shall meet the requirements for

electromagnetic compatibility (EMC) in GB 14048.1-2006 and GB/T 11022-

1999.

5.4 Environmental requirements

5.4.1 Alternated damp heat test

The common type electrical apparatus for mining use shall meet the

requirements for the damp heat test in GB/T 12173. The severity of the

alternated damp heat test is as follows. the high-temperature is 40 °C. Test

period. 6 d for instruments and meters, 12 d for low-voltage electrical apparatus,

7.1.3 Exit-factory inspection

The exit-factory inspection is to check the defects of the material and

processing of the product. It is the inspection and test item that the

manufacturer shall carry out before exit-factory.

The exit-factory inspection & test items and the corresponding standard

provisions as cited by each test item are respectively as shown in Table B.1 of

Appendix B and Table C.1 of Appendix C in this standard.

7.2 Inspection rules

7.2.1 Inspection rules for type inspection

The electrical apparatus used for type inspection shall be a sample which

complies with the design requirements in terms of structure, manufacture,

material, etc., and pass the exit-factory inspection. If all test items (or

sequences) of the type inspection can pass the test and all the samples

subjected to the test are qualified, it can be deemed that the type inspection of

this electrical apparatus is qualified. Otherwise, it shall analyze the causes, take

measures, even improve design, workmanship, tooling, etc., until the type

inspection is qualified.

If the tested sample in the type inspection has the defects which does neither

pose a threat to safety neither reduce the main performance, meanwhile the

manufacturer provides sufficient evidence to prove that such defects are not

inherent in the design but caused by individual samples, it allows for

reinspection. The product standard shall specify the test item, quantity, and

qualification criteria which allow for reinspection.

7.2.2 Inspection rules for exit-factory inspection

The exit-factory inspection items shall be carried out one by one on each exit-

factory product. The unqualified products shall be reworked or repaired one by

one until they are fully qualified. If it cannot be repaired, it shall be scrapped.

8.1 Marking

Appendix A

(Normative)

Classification of electrical apparatus for underground coal mine

A.1 Classification by rated voltage of electrical apparatus

a) Low-voltage electrical appliances for mining use which has a rated voltage

lower than or equal to 1200 V (referred to as low-voltage electrical

appliances).

b) High-voltage electrical appliances for mining use which has a rated

voltage greater than 1200 V (referred to as high-voltage electrical

appliances).

A.2 Classification by type of electrical apparatus

a) Common electrical apparatus for mining use (referred to as the common

type "KY").

b) Explosion-proof electrical apparatus for mining use (referred to as

explosion-proof type).

1) Flameproof electrical apparatus (referred to as flameproof type "Exd l");

2) Increased safety electrical apparatus (referred to as "Exe l");

3) Intrinsic safe circuits and electrical apparatus (referred to as intrinsic

safe type "Exib I, Exia I");

4) Positive-pressure type electrical apparatus (referred to as positive-

pressure enclosure type "Exp I");

5) Oil-immersed electrical apparatus (referred to as oil-immersed type

"Exo I");

6) Sand-filled electrical apparatus (referred to as sand-filled type "Exq I");

7) Encapsulated electrical apparatus (referred to as encapsulated type

"Exm I");

8) Special electrical apparatus (referred to as encapsulated type

[translator's note. should be special type] "Exs I");

9) Composite electrical apparatus (e.g., flameproof and intrinsic safe

composite type "Exd[ib] I").

d) Auxiliary and others.

1) Flameproof low-voltage resistance box;

2) Flameproof low-voltage electromagnet;

3) Flameproof low-voltage meter box;

4) Flameproof low-voltage junction box;

5) Flameproof low-voltage latch;

6) Explosion-proof integrated protection device for the transformer of

electric coal drill;

7) Flameproof integrated protection device for lighting transformer;

8) Flameproof low-voltage leakage detection relay;

9) Flameproof high-voltage cable connector;

10) Flameproof high-voltage junction box;

11) Increased safety type low-voltage cable junction box;

12) Increased safety type high-voltage cable junction box;

13) Intrinsic safe junction box.

A.4 Classification by the operation method of electrical apparatus

a) Manual operation;

b) Energy storage operation;

c) Power operation.

A.5 Classification by arc extinguishing media of electrical apparatus

a) Air;

b) Vacuum;

c) Contactless.

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