Overview:

The LMZJ1-0.5kv low-voltage current transformer is a through-core busbar type device, and it is designed for indoor AC circuits with a rated voltage of 0.5kV or below and a frequency of 50Hz. It is widely used for current measurement, energy metering, and relay protection in low-voltage power systems. This cast resin-insulated transformer features a fixed baseplate installation, offering enhanced stability and durability.

Compliant with GB 1208 standards, the LMZJ1-0.5 delivers high accuracy (0.2, 0.5, 0.2s, 0.5s), making it suitable for a broad range of applications. Its compact design, high safety performance, and extended service life make it a dependable choice for modern low-voltage systems. Additionally, it boasts excellent resistance to high temperatures and pollutants, ensuring stable operation even in challenging environments.

Key Features:

• Specifically designed for low-voltage systems (up to 0.5kV).
• Long service life with superior stability and safety.
• High resistance to heat and pollution.
• Compact, space-saving design.

The LMZJ1-0.5 low-voltage current transformer is an ideal solution for accurate current measurement, energy monitoring, and reliable relay protection in diverse low-voltage applications.

Type Designation for LMZJ1-0.5 Current Transformer

The model designation of the LMZJ1-0.5 current transformer is structured as follows:

• L: Current transformer.
• M: Busbar type.
• Z: Casting insulation.
• J: Extended capacity.
• 1: Design code.
• 0.5: Rated voltage (kV).

Technical Data of LMZJ1-0.5kv Low-Voltage Current Transformer

• Standards Compliance: Complies with GB20840.2-2014 and IEC61869-2:2012 standards.
• Rated Voltage: 0.66kV.
• Rated Frequency:  50Hz.
• Customization: For special customer requirements, please contact us for tailored solutions.
• Accuracy Class: 0.2, 0.5, 0.2s, 0.5s.
• Rated Current: Primary current: 5A–3000A. Secondary current: 5A.
• Rated Load: Refer to Table 1 for details.
• Operating Conditions: Allows continuous operation at 110% of the rated current.
• Dielectric Strength: Secondary winding can withstand 3kV power frequency voltage to ground for 1 minute without breakdown or flashover.
• Customization: For special customer requirements, please contact us for tailored solutions.

Model	Current Ratio (A)	Through-turns (Turns)	Rated Load (VA)
			Class 0.2	Class 0.5	Class 0.5S
LMZ1-0.5 LMZJ1-0.5	30	5	5－3.75	5－3.75	5－3.75
	50	3	5－3.75	5－3.75	5－3.75
	75	2	5－3.75	5－3.75	5－3.75
	100	2	5－3.75	5－3.75	5－3.75
	150	1	5－3.75	5－3.75	5－3.75
	200	1	5－3.75	5－3.75	5－3.75
	250, 300	1	5－3.75	5－3.75	5－3.75
	400, 500	1	5－3.75	5－3.75	5－3.75
	600－1200	1	10－3.75	10－3.75	10－3.75
	1500－2500	1	15－3.75	15－3.75	15－3.75
	3000	1	20－3.75	20－3.75	20－3.75

Note: The LMZJ1-0.5 current transformer allows continuous operation at 110% rated current and withstands 3kV power frequency voltage for 1 minute without breakdown or flashover.

Operating Environmental Conditions

• Primary Location: Indoor use.
• Ambient Temperature: -5°C to +40°C.
• Relative Humidity: Not exceeding 80%.
• Altitude: Installation at altitudes not exceeding 1000 meters.
• Atmospheric Conditions: Free from severe contamination, corrosive substances, or explosive media that may adversely affect the transformer’s insulation.

Structure of LMZJ1-0.5 Low-Voltage Current Transformer

• The core of the transformer is made from cold-rolled oriented silicon steel sheets, wound into a toroidal shape, ensuring high magnetic efficiency.
• The secondary winding is uniformly distributed around the toroidal core for consistent performance.
• The central window allows for busbar passthrough, while the base at the bottom provides a secure mounting option.
• The outer structure is cast with unsaturated resin insulation, offering excellent durability, safety, and resistance to environmental factors.

Outline and Dimensions of Installation

Type	Current Ratio	H	h	φD	φd
LMZ1-0.5	5-300/5	117	68	90	30

Type	Current Ratio	H	h	φD	φd	a	b
LMZJ1-0.5	5-300/5	118	70	91	32	10	41
	400-600/5	128	75	97	43	12	52

Type	Current Ratio	A1	A2	B	h	H	L1	L2	C	b
LMZJ1-0.5	1000/5 1200/5 1500/5	172	104	30	80	140	156	123	41	50
	2000/5 3000/5	216	140	42	102	182	175	150	46	70
	4000/5 5000/5	238	150	55	117	220	230	180	60	94

Installation Instructions for LMZJ1-0.5 Current Transformer

Wiring for Standard Current Transformers: For a solid-core current transformer, the primary current enters through the P1 terminal and exits through the P2 terminal. P1 is connected to the power source side, while P2 is connected to the load side.

Wiring for Through-Core Current Transformers: The wiring method for a through-core current transformer is similar to that of a standard transformer. The primary current passes through the P1 side of the transformer and exits through the P2 side. The secondary wiring follows the same procedure as standard transformers.

Secondary Side Wiring: The secondary current flows out of the S1 terminal, enters the positive terminal of the ammeter, exits from the ammeter’s negative terminal, and returns to the S2 terminal of the current transformer. It is recommended to ground the S2 terminal for safety and stability.

FAQs for LMZJ1-0.5 Current Transformer

1. What are the primary applications of the LMZ-0.5 and LMZJ1-0.5kv Current Transformers?
   They are used for accurate current measurement, energy metering, and relay protection in low-voltage power systems.
2. What standards do these transformers comply with?
   The transformers adhere to GB1207 and IEC60044-2:2003 standards for reliability and performance.
3. Are these transformers suitable for outdoor use?
   No, they are designed exclusively for indoor applications.
4. What is the rated insulation level of the LMZ-0.5 and LMZJ1-0.5kv?
   The transformers feature a rated insulation level suitable for 0.5kV systems.
5. Can these transformers be customized?
   Yes, they can be tailored to meet specific operational requirements such as current ratios or dimensions.

• Instrument Transformer Fault Handling: A Technical Guide
• Common Fault Handling for Current and Voltage Transformers
• 3 Voltage Transformer Faults and Solutions: Ensuring Accurate Measurement and Protection
• Analysis and Troubleshooting of Common Issues with Current Transformers
• Error Analysis and Maintenance of Current Transformers in Power Systems
• 4 Common Causes of 10kV Three-Phase Five-Pole Voltage Transformer Failures and Solutions