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MT 175-1988 English PDF

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MT 175-1988: Electronic protector intended to be used in flameproof electromagnetic starters used in mines
Status: Obsolete

Standard ID	Contents [version]	USD	STEP2	[PDF] delivered in	Standard Title (Description)	Status	PDF
MT 175-1988	English	639	Add to Cart	4 days [Need to translate]	Electronic protector intended to be used in flameproof electromagnetic starters used in mines	Obsolete	MT 175-1988

PDF similar to MT 175-1988

Standard similar to MT 175-1988

GB/T 3836.11 GB/T 3836.1 GB 3836.14 MT/T 1177 MT/T 907

Basic data

Standard ID	MT 175-1988 (MT175-1988)
Description (Translated English)	Electronic protector intended to be used in flameproof electromagnetic starters used in mines
Sector / Industry	Coal Industry Standard
Classification of Chinese Standard	K35
Word Count Estimation	16,190
Date of Issue	4/18/1988
Date of Implementation	7/1/1988
Quoted Standard	GB 1497; GB 3836.1; GB 3836.2; GB 3836.3; GB 3836.4; GB 2423.4; JB 3115; GB 1498; GB 6162; GB 3797; GB 998
Summary	This standard specifies the flameproof electromagnetic starter applications of electronic protection product classification, technical requirements, test methods, inspection rules. This standard applies to AC 50Hz, voltage up to 1140V of mine has one or more protection functions of the electronic protection flameproof electromagnetic starter consisting mainly of electronic components.

MT17:

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Electronic protector intended to be used in flameproof electromagnetic starters used in mines Ministry of Coal Industry Standards MT/T 175-1988 Electronic protector for mine explosion-proof electromagnetic starter 1988-04-18 ratified 1988-07-01 implemented Approved by the Ministry of Coal Industry of the People's Republic of China

1 Topic content and scope of application 1 2 Normative references 1 3 Terms and symbols 1 4 Product Category 2 5 Technical requirements 3 6 Test method 8 7 Inspection rules 12 8 Marking, packaging, transportation, storage 13 Electronic protector for mine explosion-proof electromagnetic starter

1 Topic content and scope

This standard specifies the product classification, technical requirements, test methods, inspection rules, etc. of electronic protective devices for explosion-proof electromagnetic starters for mining. This standard is applicable to mine explosion-proof electromagnetic starters with AC 50Hz and voltage up to 1140V. Electronic protector with one or more protection functions.

2 Reference standards

GB 1497 Basic Standard for Low Voltage Electrical Apparatus GB 3836.1 ~ 3836.4 Explosion-proof electrical equipment for explosive environments JB3115 General technical requirements for power system protection, automatic relays and devices GB 2423.4 Basic Environmental Test Procedures for Electrical and Electronic Products Test Db. Alternating Humidity Test Method GB 1498 motor, low-voltage electrical enclosure protection class GB 6162 Electrical interference test for static relays and protection devices GB 3797 Electrical Control Equipment Part II Electrical Control Equipment with Electronic Devices GB 998 Basic test methods for low-voltage electrical appliances

3 Terms and symbols

3.1 Thermal state For the motor, it means the state after the temperature rise of each part of the motor running under the rated load for a long time has stabilized; for the electronic protector In terms of setting, it means that the primary side of the electronic circuit of the electronic protector reaches a stable state through a set current or a specified current. 3.2 Cold state For a motor, it means the state where the temperature of each part of the motor is not running is zero; for an electronic protector, it means that the primary side is blocked The current makes all links of the electronic circuit of the electronic protector reach a stable state. 3.3 Thermal accumulation coefficient c When the motor is working, the heat generated by various losses cannot be completely dissipated immediately when it stops working, which is called the motor heat accumulation effect. In order to describe the ability of an electronic protector to simulate the heat accumulation effect of a motor, define the heat accumulation coefficient c, calculated according to formula (1). 3.4 Leakage protection Check the insulation resistance of the three-phase power supply line and the motor winding to ground by using a method such as an additional DC power supply before power transmission. When the specified value is reached, the explosion-proof electromagnetic starter cannot be closed for transmission. 3.5 Automatic reset After the protective action of the electronic protector occurs, as long as the fault causing the protective action disappears, immediately or after a certain time delay, the electronic protector The protector can be restored to its original state, which is called automatic reset. 3.6 Power-off reset The electronic protector cannot be reset automatically. The electronic protector must be interrupted for a certain period of time before it can return to its original state, which is called power-off reset. 3.7 Manual reset The electronic protector cannot be reset automatically.The electronic protector must be pressed or toggled after a specific button or switch dedicated to resetting. The ability to return to the original state is called manual reset. 3.8 Disconnection (phase) overload protection When the motor's power supply line is broken (or the winding is out of phase), if the undisconnected (phase) current increases beyond the rated value, use the detection This overload signal achieves disconnection (phase) protection, which is called disconnection (phase) overload protection. 3.9 Wire break (phase) fault detection and protection When the motor power supply line is broken (or the winding is out of phase), the fault signal is used to detect the disconnection (phase) current is zero. Line (phase) protection is called disconnection (phase) fault detection protection. 3.10 Imbalance protection When the motor has three-phase power supply line current imbalance (or three-phase winding current imbalance) reaches a certain level, protection is achieved, which is called unbalance protection.

4 Product Categories

4.1 The electronic protector shall have one or more of the following protection functions. a. Motor overload protection; b. Short circuit protection of the motor and its power supply lines; c. Motor disconnection (phase) overload protection or disconnection (phase) fault detection protection or imbalance protection; d. Leakage blocking protection of power supply lines and their motors; e. Other protection. 4.2 The specifications of the electronic protector shall be compatible with the ratings of its matching flameproof electromagnetic starter. 4.2.1 The maximum setting current value of the electronic protector should be equal to or greater than the rated current value of its matching flameproof electromagnetic starter, and its preferred series The values are 400A; 315A;.200A; 100A; 40A. Refer to Table 1 for the recommended value of electronic protection device setting current binning priority. 4.3 The basic structure of electronic protectors is divided into two categories. a.Integral type. The main part of the electronic protector is one piece, including sensor elements such as current transformers, which completes the electrical protection of various protection functions. Plug-ins, power supplies, etc. b. Combination. The main part of the electronic protector is composed of two or more parts.

5 Technical requirements

5.1 Working conditions and installation conditions 5.1.1 Working conditions 5.1.1.1 The altitude does not exceed.2000m. 5.1.1.2 Ambient air temperature. a. The ambient maximum air temperature is divided into two levels, which are listed in Table 2; b. The minimum ambient air temperature is -5 ° C. 5.1.1.3 The relative humidity of the surrounding air is not more than 95% (25 ° C). 5.1.1.4 The pollution level is Class 3 specified in GB 1497. 5.1.1.5 There should be no significant shaking and shock vibration in the workplace (when there are shock and vibration requirements, the user shall negotiate with the manufacturer). 5.1.1.6 The power supply voltage fluctuation of the electronic protector does not exceed the range listed in Table 3. 5.1.2 Installation conditions 5.1.2.1 The normal installation conditions shall be in accordance with the manufacturer's instructions, if the installation orientation is required or the performance is significantly affected by the installation conditions, it shall be in Clearly stated in the instructions. 5.1.2.2 Installation category (over-voltage category). The integral electronic protector takes the category Ⅲ specified in GB 1497; the combined electronics are installed separately The electronic plug-in part of the protector is Ⅰ. 5.2 Protection characteristic requirements The protection function possessed by the electronic protector shall meet the technical requirements specified in this article. The corresponding technical requirements and test methods shall be separately specified in the product technical conditions. 5.2.1 Overload protection characteristics 5.2.1.1 For electronic overload protectors for general explosion-proof asynchronous motor winding overload protection, their protection characteristics are shown in Table 4. 5.2.1.2 The electronic overload protection characteristic for constant load below 100A can be selected from series La group, 100A and above or used in variable Electronic overload protector for dynamic load. For the overload protection feature, series Lb group is preferred. 5.2.1.3 The thermal accumulation coefficient c of the electronic overload protector shall be greater than 20% and less than 70%. 5.2.2 Short-circuit protection characteristics 5.2.2.1 When an explosion-proof electromagnetic starter is provided with an electronic protector with a short-circuit protection function, it is required that the main contactor of the electromagnetic starter is allowed to be disconnected The current value must be greater than the actual three-phase maximum short-circuit current value. 5.2.2.2 The short-circuit protection characteristics of electronic protectors are shown in Table 5. 5.2.2.3 The manufacturer shall provide the time/current characteristics of the overcurrent protection (overload protection and short circuit protection) of the electronic protector in the form of a curve family. And draw the error ranges of these curves in an appropriate way, but must meet the requirements of Table 4, Table 5, and Table 8 of this standard; For a uniform representation of sexuality, see Article 5.8 of GB 1497. 5.2.3 Phase failure protection characteristics 5.2.3.1 The phase failure protection characteristics of the electronic protector are shown in Table 6. 5.2.3.2 Electronic protector (including groups Pa, Pb, Pc) Any two phases are connected with rated current, and the other phase is connected with 0.9 times the rated current. Start the test, the electronic protector should not work for a long time. 5.2.3.3 Group Pa belongs to disconnection (phase) overload protection, for electronic phase-break protectors below 100A; Pb belongs to disconnection (phase) Detection and protection; group Pc is unbalanced protection, which is preferred for electronic phase-break protectors with 100A and above. 5.2.4 Leakage protection 5.2.4.1 The detection signal of the leakage protection electronic protector is to be switched off after the AC contactor breaks off the arc and the residual magnetic induction potential of the motor disappears. It is required that neither the electric sparks nor the thermal effects generated during normal operation or specified fault conditions can ignite the specified explosive mixture. 5.2.4.2 Each type of leakage blocking electronic protector must clearly indicate the distributed capacitance of the external circuit to ensure the safety required by 5.2.4.1 With the maximum value of the inductance, and obtain a safety certificate inspected by the nationally recognized explosion-proof inspection agency. 5.2.4.3 In the case of the maximum distributed capacitance of the external circuit allowed by the electronic protector, the capacitor discharge and the detection power generation pass The average current of 1kΩ resistor for 1s should not be greater than 15mA. 5.2.4.4 Effective measures shall be taken to prevent the leakage of the grid voltage and the residual magnetic induction potential of the motor caused by the arc when the contactor is disconnected from blocking the leakage There are at least two methods to detect the impact of the circuit. a.Using the detection circuit to delay the contact in series; b. Take measures without closing the contacts in series to make the detection circuit of the leakage blocking electronic protector able to withstand a certain voltage surge hit. When this method is used, it is required that the detection terminal of the leakage lock electronic protector and the ground can withstand the rated line voltage of the monitored power supply system for 3s. There is no damage between the time, and its current value should not be greater than Table 7. Table 7 Voltage level ≤380 660 1140 Current value mA 5.2.4.5 Leakage blocking resistance value of the leakage protection electronic protector can be adjusted in two ways. continuously adjustable and fixed.The setting value is taken as 2 ~ 3 times of the setting value of the leakage detection relay of the power supply system. 5.2.4.6 The unlocking resistance value of the leakage blocking electronic protector shall not be greater than the set leakage blocking resistance value by 150%. 5.2.4.7 For earth leakage latch-up protectors that do not use series delay closing contacts, the detection voltage ground polarity shall be the same as the power supply system Leak detection relays have the same polarity as the ground voltage. 5.3 Product performance requirements 5.3.1 Export performance 5.3.1.1 The performance and requirements of the relay contacts of the electronic protector shall comply with the provisions of Article 4.6 of JB3115, which type is selected specifically Provided by product technical conditions. 5.3.1.2 When the power supply voltage of the electronic protector drops from the rated value to 60% of the rated value, within 16s, the outlet status of the electronic protector should not be Changed. 5.3.1.3 The electronic protector shall have a certain test button or switch to perform the necessary checks on the function of the protector. The test button or switch It can be connected externally, and specific items are stipulated by product technical conditions. 5.3.1.4 The electronic protector with display function has priority to use the following color coding. green in normal work, yellow in overload, red in short circuit The leakage current is blue, and the phase failure is white. 5.3.1.5 When the outlet circuit of the electronic protector only has a protective action function, its electrical life shall not be less than 3000 times. 5.3.2 Error (or worsening) The errors (or variations) of various types of electronic protectors include scale value errors, operating value errors and variations, power supply voltage fluctuation additional errors, temperature Additional error of degree change, its allowable range is shown in Table 8. The components of the combined electronic protector shall be interchangeable, and shall still meet the requirements of Table 8 after the interchange. MT/T 175-1988 Table 8 Group δza δzb δzc Product Categories Big error Electronic protector Average error Electronic protector Less error Electronic protector Allowable range,% is less than Scale value error ΔSa ± 10 ± 5 ± 2 Operating value error ΔSb ± 20 ± 10 ± 5 Deterioration of the operating value ΔSc ± 20 ± 10 ± 5 Power supply voltage fluctuation additional error ΔSd ± 20 ± 15 ± 10 Additional error of temperature change ΔSe ± 20 ± 15 ± 10 5.3.3 Anti-interference performance The electronic protector should be able to withstand the interference caused by the operation of the primary, secondary or DC circuits of the power system and lightning, system accidents Voltage without causing malfunction or rejection and component damage. 5.3.4 Anti-vibration performance 5.3.4.1 Requirements for vibration test The electronic protector shall be able to withstand the vibration test in three directions as shown in Table 9. Requirements, the state of the electronic protector during the test is given by the product technical conditions. Table 9 Group vibration test requirements Va Vibration frequency Hz Single amplitude mm 0.15-- Acceleration - twenty two time min Vb Vibration frequency. 10 ~ 150Hz; Amplitude. 10 ~ 57Hz is constant value displacement single amplitude 0.15mm; 58 ~ 150Hz is constant acceleration 2g; Time. 10min, 2 ~ 2.5min for one reciprocating scan Vc Sinusoidal vibration Vibration frequency. 10 ~ 500Hz; Amplitude. 10 ~ 57Hz is constant value displacement single amplitude 0.15mm; 58 ~ 500Hz is constant acceleration 2g Time. 40min, 2 to 2.5min for one reciprocating scan; 10min resonance Random vibration Vibration frequency. 20 ~.2000Hz; Spectrum density. 0.01g/Hz; Time. 90min 5.3.4.2 Drop impact requirements before installation The electronic protector should be able to withstand the drop impact during the manufacturing, testing, and transportation before packing and during the field installation. 6.8.2 After the test, the electronic protector shall still meet the requirements of routine product testing. MT/T 175-1988 5.3.4.3 Drop impact requirements after installation After the electronic protector is installed in the electromagnetic starter, it should be able to withstand the electronic protection of the starter due to overturning and falling during transportation and removal. The impact of the device, the electronic protector after testing according to 6.8.3 shall still meet the requirements of routine product testing. 5.3.5 Insulation performance 5.3.5.1 The clearances and creepage distances of components in the electronic protector that are directly in contact with the main circuit shall comply with GB 58336.3 Regulations. The electrical clearance and creepage distance between the detection signal circuit of the leakage blocking electronic protector and the exposed conductor of other circuits should be consistent In accordance with the provisions of Article 4.6 of GB 3836.4, the creepage distance of printed circuit boards shall comply with the provisions of Article 4.6.1 of GB 3836.4. 5.3.5.2 The parts of the electronic protector that are in direct contact with the main circuit shall ensure the AC 50Hz test voltage (effective value) listed in Table 10. It lasted 1min without breakdown or flashover. Table 10 Rated voltage of main circuit 127 220 380 660 1140 Test voltage 2000 2400 3000 4200 5.3.5.3 The parts of the electronic protector that are in direct contact with the main circuit shall be able to pass the pulses specified in 7.2.2.a of GB 1497. Impact test. 5.3.5.4 The electronic protector must be subjected to 12 cycles of moisture resistance test in accordance with GB 2423.4 Test Db. Alternating Humidity Test Check. The insulation resistance value of the parts directly in contact with the main circuit after the test shall not be less than the data listed in Table 11 and be able to withstand Article 5.3.5.2 For the test with a specified withstand voltage of 80%, after the moisture resistance test, the rest of the electronic protector (including the leakage detection terminal) is not evaluated for its insulation. Resistance, but the electronic protector should still meet the requirements of product routine testing. Table 11 Rated voltage of main circuit 127 220 380 660 1140 Insulation resistance value MΩ 1 1.5 2 2.5 5.3.5.5 Whether the test product should be treated before the routine test of the product after the moisture resistance test shall be specified by the product technical conditions. 5.3.6 Temperature rise 5.3.6.1 The maximum allowable temperature rise of the surface of the electronic protector is shown in Table 12. Table 12 Group TNa TNb Temperature rise 5.3.6.2 If the electronic protector uses electromagnetic components such as current transformers as sampling components, its stable temperature rise should be lower than the selected insulation material Allowable temperature rise, but at the same time must not exceed the data in Table 12. 5.4 Components and structural requirements 5.4.1 The parts of electronic protectors must be standard parts first, and should meet the requirements of national, industry or enterprise product standards, respectively. 5.4.2 The semiconductor components used in electronic protectors must be screened by aging, and the method shown in Table 13 is preferably used. Power components should be based on No. 1, 2, and 3, non-power components according to No. 1, 2. MT/T 175-1988 Table 13 Sequence name method

1 High temperature storage

Place the non-operating components in a high temperature box (125 ° C for silicon components, 70 ° C for germanium components), constant temperature 24h

2 High and low temperature impact

Place the non-operating device at low temperature (-30 ° C) and high temperature (125 ° C for silicon device, germanium device) 70 ° C) for 30min each, the interval should be less than 1min, and reciprocating 3 times 3 When electrical aging at room temperature (20 ± 5 ℃), make the component work at rated power for 8h 5.4.3 The method for selecting qualified semiconductor components is. a. Test after aging, the relevant parameters should meet the technical standards specified by the product or the standards formulated by the manufacturer; b. Perform the initial test before aging and the retest after aging. It is required that the parameters of the second measurement should all meet the technical standards specified by the product or the manufacturer. In addition to the formulated standards, the parameter changes should not exceed 20%, and the ambient temperature for parameter testing is specified by the manufacturer. 5.4.4 From the detection terminal of the leakage blocking electronic protector to the end of the series delay normally closed contact or the series normally closed contact used to access the main circuit The wires between them are marked with blue insulated wires or blue sleeves. 5.4.5 The printed circuit board in the electronic protector shall not use paper or cloth insulation board, and the surface of the printed circuit board shall be provided with an insulating coating. Apply more than twice. 5.4.6 When the plug-in connector is used for the electronic protector, its contact part should be gold-plated, or at least silver-plated to ensure its reliability and connect with external circuits There should be a positioning device between the plug and the socket to ensure that each plug-in point has a unique corresponding relationship when plugging in. The plug-in box and the base should be tight. Fixing or locking devices, plugs and sockets, plug-in boxes, and bases should be sealed to ensure the overall pr...

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