JB/T 5555-2013Transformers for Machine Tools (English PDF)

3.1 Terms and definitions

The terms and definitions as defined in GB/T 2900.1, GB/T 2900.15, GB 14048.1-2006, as well as the following terms and definitions, apply to this document.

3.1.1 Transformers for machine tools

Transformers with two or more electrically isolated windings, used as power supplies for control circuits, lighting circuits, signal circuits, electronic equipment in the electrical systems of machine tools and other mechanical equipment.

3.1.2 Rated supply voltage

The nominal voltage applied to the input terminal of the transformer, under normal operating conditions.

3.1.3 Rated output voltage

The nominal value of the transformer output voltage, under normal operating conditions.

3.1.4 Rated output power

The rated output power is equal to the product of the rated output voltage multiplied by the rated output current of the transformer. When the transformer has multiple independent output windings, the rated output power is equal to the sum of the products of the rated voltage of each output winding multiplied by the rated current of the winding.

3.1.5 No-load output voltage

The output voltage when no-load at rated supply voltage and rated frequency.

3.1.6 Load output voltage

The output voltage, when rated power is output at rated supply voltage and rated frequency.

3.1.7 Output voltage of instantaneous power

The output voltage, when instantaneous power is output at rated supply voltage and rated frequency.

3.2 Symbols

The main symbols specified in this document are as follows. Ue - Rated supply voltage; UH - Rated output voltage; Ui - Rated insulation voltage; Uk - No-load output voltage; Um - Load output voltage; Um Phi - Output voltage of instantaneous power.

5.1 Structural type

The transformer is generally an open structure; it can also be made into a shell structure if necessary.

6.1 Information content

The manufacturer shall specify the following related information.

a) Manufacturer name or trademark;

b) Product model and (or) name;

c) Standard number that the product complies with;

d) Year and month of manufacture;

e) Rated output power, rated supply voltage, rated output voltage (see 5.2.2.1);

f) Rated frequency (see 5.2.2.2);

g) Rated capacity of each output winding (if applicable);

h) Rated insulation voltage (see 5.2.2.3);

i) IP rating (if applicable) (see 8.1.6);

j) Pollution level (see 7.1.3.2);

k) Conformity mark and certification mark (if applicable).

6.1 The information content of items a) ~ g) shall be marked on the nameplate of the transformer, so that complete information can be obtained from the manufacturer. The markings shall be clear, indelible, easily identifiable, which shall not be marked on screws and movable parts. If the location permits, the parameters of items h) ~ k) may also be marked on the nameplate or transformer, or included in the documents published by the manufacturer.

6.2 Marking

6.3 Installation, operation, maintenance instructions

The manufacturer shall specify the installation, operation, maintenance conditions of the transformer during operation and after a fault, in its documents (such as the instruction manual) or samples (if any).

If necessary, the transportation, installation, operation instructions of the transformer shall specify the appropriate and correct installation, transportation, operation methods of the transformer.

The manufacturer shall provide instructions, to recommend what measures the user shall take to prevent short circuits.

6.4 Packaging

6.4.1 Packaging box (inner packaging)

The packaging box shall be accompanied by a product certificate; the packaging box marking shall include the following.

a) Manufacturer name or trademark;

b) Product model and name and year and month of manufacture;

c) Rated output power, rated supply voltage, rated output voltage, rated frequency.

6.4.2 Packing box (outer packaging)

The transformer packaging box shall be sturdy, moisture-proof, dust-proof, which is suitable for transportation. The box shall contain a packing list, product instructions, etc. The gross weight of each box shall not exceed 50 kg. The outer wall of the packaging box shall have obvious and durable markings, indicating the following information.

a) Manufacturer name, address or trademark;

b) Product model and name;

c) Product number;

d) "Length × width × height" dimensions and gross weight of the packaging box;

e) Name and address of the consignee;

f) Markings such as "Fragile items", "Avoid rain", "Keep upward", "Packing year and month" or other words or signs.

Other requirements shall also comply with the provisions of GB/T 13384.

The installation category of the transformer is specified as "Installation category III".

7.1 Normal use conditions

7.1.7.4 of GB 14048.1-2006 applies.

7.1.9.1 of GB 14048.1-2006 applies.

7.1.9.2 of GB 14048.1-2006 is applicable. The following content is supplemented.

a) The protective grounding terminal of the transformer shall have measures to prevent loosening and shall not be used for other fastening purposes;

b) The body of the protective grounding terminal shall use screws or parts with the same function as screw connection; have appropriate anti-corrosion measures.

There shall be a clear protective grounding mark near the protective grounding terminal;

c) The minimum diameter of the grounding screw is M4.

7.1.9.3 of GB 14048.1-2006 is applicable.

7.2 Installation conditions

7.2.2 Installation direction

The transformer can be installed in any direction.

7.2.3 Installation method

The transformer is fixed with screws.

Note: The requirements of other installation methods are negotiated by the manufacturer and the user.

7.3 Transportation and storage conditions

If the transportation and storage conditions of the transformer, such as temperature and humidity, are different from those specified in 7.1, the manufacturer and the user shall reach a special agreement. Unless otherwise specified, the following temperature range applies to transportation and storage. within -25 °C ~ 55 °C, up to 70 °C for a short time (24 h).

8.1 Structural requirements

The transformer for type test shall be a formal trial-produced sample. Each test item shall be no less than two products. All specified type test items shall be qualified, before the transformer type test is considered qualified. If one item of a product is unqualified, it is allowed to double the number of original test products for retest. If all items are qualified in the retest, the type test can still be considered qualified. If another item of a product is unqualified, it shall analyze the cause and take technical measures to re-test the item, until the test is qualified. Products that pass the type test can be submitted for identification.

8.1.1 General requirements

The transformer shall be designed to withstand the stress generated during transportation, installation, normal use; meanwhile meet the requirements of relevant tests.

8.1.2 Materials

The insulating material parts of the transformer shall be resistant to abnormal heat and fire. The verification test may be carried out in the following appropriate ways.

a) On the transformer;

b) On the parts of the transformer;

c) On the test piece of the same material with appropriate cross-sectional area.

If the same material with the same cross-sectional area has met the test requirements specified in 9.2.1, it is not necessary to repeat the test.

8.1.5 Protective grounding requirements

8.1.5.1 Structural requirements

8.1.5.2 Protective grounding terminal

8.1.5.3 Marking and identification of protective grounding terminals

8.1.6 Degree of protection by shells

The transformer shell (if any) shall be designed according to the location and environmental conditions of the transformer installation site; its degree of protection shall comply with the provisions of 6.2.2 of GB 5226.1-2008.

8.1.7 Moisture resistance

The transformer shall be able to withstand the alternating damp heat test, at a high temperature of 40 °C and a test cycle of 6 days and nights.

8.1.8 Component quality

The metal parts of the transformer shall have reliable anti-rust protection measures.

The surface of the plastic parts of the transformer shall be smooth; there shall be no clamping, cracking, bubbles, pitting, serious scratches.

The electroplated parts of the transformer shall not have plating shedding.

8.1.9 Assembly quality

The connecting screws of the transformer shall be tightened without loosening;

9.1 Classification of tests

9.1.3 Routine test

Routine test is a test conducted on each transformer during or after the assembly of the product. The purpose is to check for defects in materials, processes, assembly. The test is allowed to be carried out using a fast equivalent method. Routine tests include the following items.

a) Dielectric performance test (see 9.3.3);

b) No-load loss test (see 9.3.6);

The efficiency test (see 9.3.10) is a special test for transformers.

9.2 Verification of structural requirements

c) Mechanical properties test of terminal blocks (see 9.2.3);

d) Protective earth terminal inspection (see 8.1.5);

e) Test of degree of protection by shell (if applicable) (see 9.2.4);

f) Moisture resistance test (see 9.2.5);

g) Dielectric properties test (see 9.3.3);

h) Induction withstand voltage test (see 9.3.4);

i) Temperature rise test (see 9.3.5);

j) No-load loss test (see 9.3.6);

k) No-load output voltage test (see 9.3.7);

l) Load output voltage test (see 9.3.8);

m) Output voltage test under instantaneous power conditions (if applicable) (see 9.3.9);

n) Other tests (including inspection of external dimensions and installation dimensions, markings, component quality, assembly quality, etc.) (see 5.3, 6.2, 8.1.8, 8.1.9).

9.2.1 Abnormal heat and fire resistance test

9.2.1.1 Glow wire test (performed on transformer)

The abnormal heat and fire resistance test of insulating material parts adopts the glow wire test method and is carried out in accordance with the provisions of GB/T 5169.10-2006 and GB/T 5169.11-2006.

a) Insulating material parts used for fixed current-carrying parts shall adopt a glow wire top temperature of 960 °C ± 15 °C, for a duration of 30 s ± 1 s, two pieces of each type;

b) Insulating material parts used for non-fixed current-carrying parts shall adopt a glow wire top temperature of 650 °C ± 10 °C, for a duration of 30 s ± 1 s, two pieces of each type;

c) The test results shall be determined in accordance with the requirements of GB/T 5169.10-2006 and GB/T 5169.11-2006.

9.2.1.2 Flame test, heating wire ignition test and arc ignition test (performed on materials)

9.2.2 Measurement of electrical clearance and creepage distance

Appendix G of GB 14048.1-2006 is applicable.

9.2.3 Mechanical property test of terminal blocks

The mechanical property test of transformer's terminal blocks shall be carried out in accordance with 8.2.4 of GB 14048.1-2006.

9.2.4 Test of degree of protection by shell

Appendix C of GB 14048.1-2006 is applicable.

9.2.5 Moisture resistance test

Appendix K of GB 14048.1-2006 is applicable, supplemented by the following.

The insulation resistance after the test shall not be less than that specified in Table 11.

According to the agreement between the manufacturer and the user, a transformer with a rated frequency of 60 Hz can be tested under 50 Hz conditions; the validity of the test shall be confirmed according to the content of the agreement.

9.3 Verification performance requirements

9.3.3 Dielectric performance test

The dielectric performance test of the transformer shall be carried out on a clean and dry product. At the power frequency withstand voltage test's voltage value specified in Table 4, the type test lasts for 5 s; the routine test can be shortened to 1 s; there shall be no breakdown or flashover during the test; the leakage current shall not be greater than 100 mA.

The voltage of power frequency withstand voltage test is applied at.

- Between the input winding and the output winding;

- Between the input winding, the output winding and the core;

- Between the output windings.

If the transformer has passed the dielectric performance test as required, when the withstand voltage test is repeated afterwards, the test voltage shall be reduced to 85% of the original test voltage value.

9.3.4 Induction withstand voltage test

Any winding of the transformer is applied with twice the rated voltage and twice the rated frequency of the winding, whilst the other windings are open-circuited for 5 minutes. If a higher frequency is used, it shall not be less than 2 minutes. The inter-turn insulation shall not be broken down.

9.3.5 Temperature rise test

The input winding of the transformer is at the rated supply voltage and rated frequency; the output winding is connected to the rated load with a power factor of cos phi = 1.The test circuit is as shown in Figure 1. After the transformer reaches thermal stability, the temperature rise of each component of the transformer is measured, which shall meet the requirements of 8.2.3. The test is carried out in accordance with the provisions of 8.3.3.3 of GB 14048.1-2006. […]