Littelfuse

T2900.0020

Name: Littelfuse T2900.0020 Differential Current Relay, 230V 5A, protects generators with digital timer and visual indicators.
Brand: Littelfuse
SKU: T2900.0020
Availability: InStock

UPC: 079458962932

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Overview

The **Littelfuse T2900.0020 Differential Current Relay** is a high-performance protection device engineered to safeguard generators and critical electrical systems from harmful differential currents. Rated for **230V AC and 5A**, this relay delivers precise monitoring and rapid response to fault conditions, preventing equipment damage, downtime, and safety hazards. Designed for industrial, commercial, and utility applications, the T2900.0020 integrates seamlessly into generator protection schemes, ensuring compliance with stringent safety standards while optimizing operational reliability. **Key Features and Benefits:** - **High-Precision Digital Countdown Timer:** The built-in digital timer allows for adjustable delayed output, enabling engineers to set trip delays tailored to specific system requirements. This feature is critical in applications where nuisance tripping must be avoided, such as in parallel generator systems or sensitive industrial processes. - **Clear Visual Indicators:** The relay provides **three distinct LED indicators** for power status, pick-up (fault detection), and relay tripping. This real-time feedback simplifies troubleshooting, reduces maintenance time, and enhances operational transparency for technicians and engineers. - **Built-in Energy Source for Uninterrupted Operation:** Unlike conventional relays that fail during power loss, the T2900.0020 incorporates an internal energy storage system, ensuring **continuous protection** even in the event of a supply failure. This is particularly vital in mission-critical applications such as hospitals, data centers, and emergency power systems. - **Compact and Robust Design:** The T2900.0020 is engineered for durability, with a rugged housing that withstands harsh industrial environments, including vibration, temperature fluctuations, and electromagnetic interference. Its compact form factor simplifies installation in control panels and switchgear, saving valuable space. - **Wide Compatibility and Easy Integration:** Compatible with standard generator protection schemes, the relay supports **ANSI/IEEE device numbers 87G (Generator Differential Protection)**, making it a versatile choice for new installations or retrofits. Its **230V AC rating** aligns with global power standards, ensuring broad applicability across regions. **Typical Applications:** The Littelfuse T2900.0020 is ideal for a variety of critical applications where generator protection is paramount: - **Power Generation Plants:** Protects generators from internal faults, such as stator winding short circuits or ground faults, which can cause catastrophic damage if undetected. - **Industrial Facilities:** Used in manufacturing plants, refineries, and chemical processing units where reliable backup power is essential to prevent production losses and safety risks. - **Commercial Buildings:** Ensures uninterrupted power for hospitals, data centers, and financial institutions by detecting and isolating faults in emergency power systems. - **Renewable Energy Systems:** Provides differential protection for wind turbines and solar power inverters, safeguarding sensitive electronics from current imbalances. - **Marine and Offshore Platforms:** Delivers robust protection in harsh maritime environments, where power reliability is critical for navigation, communication, and safety systems. **Why Choose Littelfuse?** Littelfuse is a globally recognized leader in circuit protection, power management, and electrical safety solutions, with over a century of innovation and expertise. The **T2900 series** reflects the company’s commitment to delivering high-reliability products that meet the demands of modern industrial applications. Engineers and procurement professionals trust Littelfuse for its **rigorous testing, compliance with international standards (IEC, UL, ANSI)**, and responsive technical support. By selecting the T2900.0020, you gain not just a relay—but a **proven solution backed by a trusted manufacturer** with a legacy of protecting critical infrastructure worldwide. **Installation and Maintenance Considerations:** Proper installation of the T2900.0020 is straightforward, thanks to its **modular design and clear wiring terminals**. Professionals should follow industry best practices, such as: - Ensuring correct polarity and grounding to avoid false tripping. - Calibrating the digital timer based on system fault characteristics. - Regularly inspecting visual indicators and performing functional tests to verify relay operation. With its **combination of precision, reliability, and ease of use**, the Littelfuse T2900.0020 Differential Current Relay is the smart choice for engineers seeking to enhance generator protection while minimizing operational risks. Whether deployed in a new installation or as part of an upgrade, this relay delivers the performance and peace of mind required in today’s demanding industrial landscape.

230V AC, 5A differential current protection for generators
High-precision digital countdown timer for adjustable trip delays
Visual indicators for power, pick-up, and tripping status
Built-in energy source ensures operation during power loss
Compact, rugged design for harsh industrial environments

Specifications

Application	Industrial
Brand Name	Littelfuse
Special Features	High Quality
Sub Brand	Relay Series
Type	Protection Relays and Controls

1-1393143-3

Relay Accessories, Sockets & Clips, Printed Circuit Board, Phenolic, Printed Circuit Board, 6, Socket, Potter & Brumfield R10

1-1393143-6

Relay Accessories, Sockets & Clips, Solder, Polyester, Printed Circuit Board, 2, Socket, Potter & Brumfield R10

RK926011-BC

RTXP 18

6896057-1

RTXD Extractor Tool

PS-60

Power supply for DIN-rail

SCP102D24X-C02

IP67 SCP-X Extreme Environment Series Power Supply. Double Stacked, Output Power 2 x 100W, Output Voltage 24 Vdc, Output Current 7.6 A total, 3.8 A per pair

C3SC10106GY

N3 SCREW COVER - 10X10X6 - GRA

ACS380-040S-07A2-4

ACS380 AC Drive, 3-380-480V In, 3HP, 6A, Type OPEN, 1.5 overload, Integrated, HxWxD 6.69x2.76x7.52 in, Module

0626030563

BK63H 1P B2A 10kA 120/240VAC UL1077

1338006700

MC-50a AC120V 50/60Hz SCREW 1a1b (Metasol) EXP (MC50A-30-11-K7-S-E)

1270040900

GMD-16M DC240V 3W 1b EXP (GMD16M-30-01-UD-3W-S-E)

1SNK705010R0000

Combine high performance with compact dimensions: - 1000 V AC / DC IEC 600 V UL, - Opt for the best marking visibility thanks to the up-front, flat marker zone, which lets you mark up to eight digits or increase the font size.

CR104PXN1B

Pushbuttons. 104P heavy duty Oiltight Pushbutton. Nameplate. XN1B PR.No. CR100699

XT2NU3090BFF000XXX

C.BREAKER TMAX XT2N 125 UL/CSA FIXED THREE-POLE WITH FRONT TERMINALS AND THERMOMAGNETIC RELEASE TMA R 90 I3=450...900 A

TEYF2110MM

110A 2P 65K 240V TEYF TENANT BREAKER

NNC75X75WH2

The NNC75X75WH2 Halogen-Free Wide Slot Wiring Duct is used to route, protect, and manage wires near sensitive electronic equipment and in environments where heat resistance or public safety is a concern. UL 94 flame class of V-0 with a UL recognized continuous-use temperature up to 95 C (203 F). Halogen-Free, Polyphenylene Oxide (PPO). Mounting holes provided. 2.85" x 2.97" (72.4 mm x 75.4 mm) and 6.6' (2 m) long. Cover included. Color White. 5 pieces per package.

3194213000K04

DS9 RECEPTACLE POLY BLUE SIZE 5 IP 66/67/69 3P+G 150 A 480 VAC 60 Hz

C2G0150MQMJ

HPS Open Style Control Transformer, 150VA 240x480V-120x240V 50/60Hz

T7900.0030

Electronic Potentiometer. 230V AC. The T7900 Electronic Potentiometer is typically used as an interface between a unit that provides increase/decrease contacts signals and electronic speed governors or voltage regulators (AVR) controlled by analogue voltage or current signals. The T7900 works much like a conventional motorized potentiometer (e.g. the E7800). However, instead of a variable resistance, the T7900 provides a variable voltage (e.g. -5 to +5 VDC), current (e.g. 4-20 mA) or a pulse width modulated signal (PWM). The voltage and current range is programmable. The PWM output provides a 500 Hz signal with programmable duty cycle. The analogue outputs are galvanically isolated.

T2400.0010

Dual Overcurrent Relay. 230V 5A. The T2400 consists of two combined over current relays, intended for protection, or monitoring of generators, power transmissions and consumer supply. A typical application for protection of a generator is for one of the over current functions to trip the generator breaker and the other over current function to trip a nonessential service. Both over current functions could be used to trip 2 levels of nonessential load. The relay detects the highest of the 3 input currents and, on exceeding the preset values, output relays will be activated after preset time delays.

E7800.0140

Motorized Potentiometer 230-240V AC,10k. The E7800 Motorized Potentiometer is typically used as an interface between increase/decrease relay contacts (or push buttons) and a device requiring control by an external potentiometer (e.g. the speed trim of an electronic governor). All three wires of the potentiometer are directly accessible on external connection terminals, thus providing the best possible flexibility for almost any application. A special version of the E7800 with DC voltage output is also available. The DC output voltage follows the position of the potentiometer. The design of the E7800 ensures that the potentiometer will “remember” its position although supply is lost

E7800.0420

Motorized Potentiomtr 230 VAC 10k 1 TURN. The E7800 Motorized Potentiometer is typically used as an interface between increase/decrease relay contacts (or push buttons) and a device requiring control by an external potentiometer (e.g. the speed trim of an electronic governor). All three wires of the potentiometer are directly accessible on external connection terminals, thus providing the best possible flexibility for almost any application. A special version of the E7800 with DC voltage output is also available. The DC output voltage follows the position of the potentiometer. The design of the E7800 ensures that the potentiometer will “remember” its position although supply is lost

D0920.0060

The D0920 Arc Detection Unit is a high-speed arc-detection device for electrical power-distribution systems. The D0920 supports up to three point sensors (A0220) mounted in a switchboard, and requires a 230 Vac supply. On the occurrence of an arc fault, the D0920 detects the fault and pulses the trip output in less than 1 ms. The fast trip time reduces the risk of personal injury and equipment damage. The D0920 is typically supplied from the switchboard main power. The AC voltage may fail when an arc fault develops. The D0920 uses energy stored in an internal capacitor to trip the circuit breaker. The storage capacitor is an extremely long-life electrolytic capacitor with a specified life time of more than 30 years at an ambient temperature of 50°C (121°F). The trip energy stored is sufficient for circuit breakers with a 220/250 Vdc shunt trip coil. The D0920 has one output indication relay with an isolated normally-open contact, and one output indication relay with an isolated normally-closed contact. Additional features include power and trip indication, test mode, and sensitivity adjustment.

T2200.0030

Overcurrent Relay230V5A Latching output. The T2200 has a broad application where all 3 phases or any single phase current detection will function for protection, control or monitoring. The relay detects the highest of the 3 input currents and, on exceeding the preset value, an output relay will be activated after a preset time delay. Available in many versions, varying in supply voltage, measuring currents, and functions.

T2000.0140

Reverse Power Relay. 230V L-L 5A. Protects the generator from being run as a motor. The Reverse Power Relay T2000 will protect the generator from being run as an electric motor. The T2000 will protect the prime mover of the generator against physical damage, but will also protect the parallel running generators from overload caused by the inversed load shift in a reverse power situation. T2000 reverse power relay function: The T2000 measures the current through an external 5A CT attached on phase L1. The phase angle (phi) is determined from the voltage measurement across L1 and L2. The T2000 calculates the active current as I x cos phi. If the active current becomes negative and exceeds the preset level (2 – 20 percent), the pick-up LED will activate and the trip delay timer (2 – 20 seconds) will also activate. The built-in trip relay will energize after the delay has passed, provided that the preset trip level was continuously exceeded during the time of the delay.

T5000.0020

Paralleling Relay. 230V. The T5000 Paralleling Relay is a check synchroniser. The T5000 has two separately insulated voltage inputs, one for each system. A built-in relay will close when voltage, frequency and phase are within safe limits. The relay output can be connected in series with a manual contact to operate the circuit breaker between the two systems. A voltage adjustment is provided on the front facia. The voltage adjustment can be set to accept closure when voltage difference between the two systems is within the range of 10 to 15percent. LED based indication of relay activity is also provided.

T3000.0010

T3000 Frequency Relay. 230V. The T3000 is intended for effective frequency surveillance on generators, busbar or other distribution systems. The relay contains the functions “under frequency” and “over frequency” time delayed, and 2 individual output relays, one relay for each function.

T3200.0010

Insulation Monitoring Relay. 230V. The Insulation Monitoring Relay T3200 is intended for continuous insulation monitoring on three phase insulated networks on board ships. The relay monitors continuously two systems galvanically separated from each other, e.g. the busbar and the lighting system, or two busbar systems. The unit features two output relays for alarm purposes and two analogue outputs for instrument reading. The instrument is not included with the relay. Instruments are available from as standard sized switchboard component.

T4500.0020

Auto Synchronizer. 230V 5A. The T4500 Auto-Synchroniser provides automatic synchronisation and connection of a generator to a live bus bar. The T4500 measures the voltage across two phases on either side of the circuit breaker in order to obtain data on frequency, phase and voltage deviation. The T4500 will automatically adjust the speed of the generator (through the governor) in order to match the frequency and phase to the live busbar. Two built-in relays provide the increase and decrease pulses for a conventional governor. The strength (width) of the pulses is proportional to the frequency/phase deviation. The E7800 Motorised Potentiometer can be used to adapt the contact pulses to a signal suitable for the speed trim input of an electronic speed controller. The T4500 will continuously adjust the generator speed until frequency and phase is within limits. The signal to close the circuit breaker is issued just before phase accordance is obtained. This is done in order to compensate for the circuit breaker make time.

T4800.0020

Load Sharer. 230V 5A. The T4800 is designed to control a generator operating in parallel with the grid, or a generator operating in parallel with other generators (which are also controlled by T4800 units). The T4800 will continuously measure and compare the active current on the generator to an external DC reference signal connected to the “parallel lines” input. The T4800 will increase or decrease the speed of the generator (through the governor) if it finds the active current level to be either too low or two high. Two built-in relays provide the increase and decrease pulses for a conventional governor. The strength (width) of the pulses is proportional to the frequency/phase deviation. The E7800 Motorised Potentiometer can be used to adapt the contact pulses to a signal suitable for the speed trim input of an electronic speed controller.

Frequently Asked Questions about Littelfuse

What certifications and standards do Littelfuse products comply with?

Littelfuse products are certified to multiple international standards, including UL (Underwriters Laboratories), CSA (Canadian Standards Association), CCC (China Compulsory Certification), and EAC (Eurasian Conformity). Customers can verify specific product certifications by consulting individual product datasheets on Littelfuse.com, which provide comprehensive details about standards compliance for each component.

What industries and applications are Littelfuse products used for?

Littelfuse products are critical for electrical protection and safety across multiple industrial sectors, including manufacturing, automation, power distribution, and electrical control systems. Their comprehensive product portfolio serves industries that require robust electrical protection, including motor and pump applications, solar installations, programmable logic controllers (PLCs), electrical switch panels, and critical infrastructure environments. Key product lines protect against overcurrent, voltage transients, ground faults, and temperature-related electrical risks, ensuring equipment safety and operational reliability.

What technical support does Littelfuse offer?

Littelfuse offers comprehensive technical support through multiple channels. Their Technical Hotline (800-TEC-FUSE) provides direct access to engineers who can help identify issues and recommend solutions. Additionally, Littelfuse offers extensive online Technical Resources at Littelfuse.com, including datasheets, product manuals, whitepapers, application guides, and online design tools. Their experienced product and application engineers also provide step-by-step support from design to installation.

What are the main product lines offered by Littelfuse?

Littelfuse offers comprehensive industrial protection and control product lines, including fuses, fuse holders, protection relays, temperature sensors, and electrical safety components. Their key product categories span surge protective devices, custom OEM products, electrical switch panels, medium voltage fuses, ground-fault protection relays, motor and pump protection devices, and temperature sensors. These products are designed to minimize electrical safety hazards, limit equipment damage, improve productivity, and safeguard personnel from electrical faults.

What are the key features of Littelfuse products?

Littelfuse products feature exceptional circuit protection technologies with key characteristics including UL/IEC safety standard compliance, low internal resistance, and advanced protective capabilities across multiple product lines. Their components provide critical protection for industrial systems, offering features like overcurrent protection, voltage transient suppression, and resettable protection devices with ultra-low resistance and compact designs. Key product lines include fuses, metal oxide varistors (MOVs), TVS diodes, PolySwitch devices, and specialized electronic protection components that enhance system reliability and safety.

What environmental ratings do Littelfuse products have?

Littelfuse products feature comprehensive environmental ratings, including NEMA Type 1, 2, 3, 3R, 4/4X, 12, and 13 certifications, as well as IP65 protection. These ratings ensure superior protection in diverse industrial environments, with an operating temperature range of -40°F to +131°F (-40°C to +55°C). Many products also include UV-stabilized materials and neoprene gaskets for enhanced durability in outdoor and challenging conditions.

What accessories are available for Littelfuse products?

Littelfuse offers several key accessories across their product lines, including fuse holders, voltage monitoring modules, and terminal connectors. Specific accessories include the LPSM003ZXID (indicating) and LPSM003Z (non-indicating) POWR-SAFE Dead Front fuse holders for Class CC and Midget-Style fuses, the VRM6048 voltage monitor accessory module, and female quick connect terminals (P1015 series) in various wire gauge sizes. These accessories are designed to enhance protection, monitoring, and connectivity for Littelfuse electrical components.

What is Littelfuse's warranty policy?

Littelfuse provides comprehensive warranty details on their official website at www.littelfuse.com/warranty. Customers should visit this page to review the specific warranty terms and conditions for their specific product lines. For direct warranty support or questions, customers can contact Littelfuse Technical Support at 1-800-TEC-FUSE or email [email protected].

What communication protocols do Littelfuse products support?

Littelfuse supports a comprehensive range of industrial communication protocols, including PROFIBUS, PROFINET, EtherNet/IP, DeviceNet, Modbus RTU, and CANopen. Our products provide flexible connectivity solutions across multiple industrial automation platforms, enabling seamless integration with various control systems and network architectures.

How are Littelfuse products typically installed?

Littelfuse products are typically installed using specialized mounting hardware like fuse holders, blocks, and panels designed for specific industrial applications. The POWR-SAFE Dead Front holders, for example, provide optimum protection for Class CC and Midget-Style fuses, supporting installations up to 600 VAC/DC. Installation often involves using precision terminals with strain relief, such as 0.25 in. female quick connect terminals, to ensure secure and safe electrical connections in industrial control systems.