MPCB Type 1 vs Type 2 Coordination Explained
IEC 60947-4-1 Type 1 permits component damage after a fault while Type 2 limits it to separable contact welding, and the choice comes down to acceptable downtime on that branch.
8 min read
Technical
Technical for buyers and panel builders
Guides and notes on industrial electrical and automation parts: selection, wiring, settings and ordering.
- Articles
- 543
MCB vs RCBO vs RCD vs RCCB: Key Differences
MCB, RCD (RCCB) and RCBO protect against different faults. This compares what each detects, the 30 mA vs 300 mA sensitivity split, and how Vigi or DS201 add-ons combine them.
9 min read
RCD Types AC, A, F, B and SI Explained
A breakdown of RCD Types AC, A, F, B and SI: the waveform each detects, why Type AC is now restricted, and how to size Type B for VFDs, EV...
9 min read
Siemens 3VA1 vs 3VA2: Thermal-Magnetic vs Electronic MCCB
Siemens Sentron 3VA1 uses a fixed thermal-magnetic trip to 630 A; 3VA2 uses an adjustable ETU (ETU320 to ETU850) to 1000 A, and the two are not interchangeable in the...
9 min read
Analog vs Digital Monitoring Relays: How Measurement Works
Analog monitoring relays set thresholds with a potentiometer and drift with age; digital relays sample via ADC, hold a fixed digital setpoint, and often add true-RMS measurement and fault memory.
9 min read
VFD Motor Bearing Currents and Shaft Grounding
PWM common-mode voltage induces shaft voltage on VFD-fed motors, which discharges through the bearing film as EDM pitting and fluting unless a shaft grounding ring, insulated bearing, or common-mode filter...
9 min read
Overload Relay vs Fuse: Why a Motor Needs Both
A fuse clears short-circuit current in a few cycles but ignores the slow, sustained overload that overheats motor windings, which is why every motor branch circuit needs an overload relay...
9 min read
Kick-Start and Pedestal Voltage on a Soft Starter Explained
Pedestal voltage sets breakaway torque on a soft starter's ramp, and kick-start is a short pulse reserved for loads that resist the first instant of rotation.
10 min read
MPCB Trip Classes 10, 20 and 30 Explained
How IEC 60947-4-1 trip classes 10, 10A, 20 and 30 govern MPCB thermal overload response, and how to match the class to a motor's start time.
9 min read
MCB Pole Configurations: 1P, 2P, 3P, 4P and 1P+N
A technical breakdown of MCB pole configurations 1P, 2P, 3P, 4P and 1P+N, covering neutral switching, module width, and TN/TT earthing-system fit for panel builders and procurement engineers.
11 min read
RCD Sensitivity: 10mA, 30mA, 100mA and 300mA Explained
A breakdown of RCD sensitivity ratings (IΔn) from 10 mA to 300 mA, covering personal versus fire protection, earth electrode sizing, and how to choose the right threshold for a...
11 min read
Schneider EasyPact CVS vs ComPact NSX: Differences Explained
A spec-level comparison of Schneider's EasyPact CVS and ComPact NSX MCCBs covering breaking classes, trip units, metering, and when the economy CVS tier is the right engineering choice.
9 min read
Main Components of a Measuring Relay: Sensing, Threshold, Output
The sensing input, threshold and hysteresis, trip delay, and output-contact stages that make up a measuring relay, and how they work together to avoid nuisance trips.
10 min read
VFD Output Filters: dV/dt, Sine Wave and Cable Length
How reflected-wave voltage forms on VFD output cables and how to choose between a dV/dt reactor, a sine-wave filter, and cable-length limits.
10 min read
Main Components of an Overload Relay: Bimetal, Trip Bar, Reset
A component-by-component look at the bimetal strips, differential trip bar, contacts, and reset mechanism inside a thermal overload relay.
9 min read
Soft Starter Settings: Ramp Time, Initial Voltage, Current Limit
How initial voltage, current limit, and ramp time settings interact on a soft starter, and the commissioning sequence that avoids nuisance trips.
10 min read
How an MPCB Protects a Motor: Thermal and Magnetic Trips
How the adjustable thermal bimetal and fixed magnetic trip inside an MPCB protect a motor branch from overload and short circuit.
8 min read
IEC 60898-1 vs IEC 60947-2: MCB Standards Compared
IEC 60898-1 covers MCBs for ordinary persons with Icn ratings in amps, while IEC 60947-2 covers industrial breakers with Icu/Ics in kA and K/Z curve options.
9 min read
How an RCD Detects Earth Leakage: Toroidal Core Principle
How an RCD's toroidal core sums line and neutral current to sense earth leakage and trip in milliseconds.
10 min read
ABB Formula vs Tmax XT: Which ABB MCCB to Choose
A practical comparison of ABB's Formula A and Tmax XT MCCB lines, covering frame overlap, breaking capacity classes, and Ekip trip options to pick the right one.
11 min read
Monitoring Relay vs Protection Relay vs PLC Monitoring
A practical comparison of monitoring relays, protection relays, and PLC-based monitoring that explains what each device does, where their functions overlap, and how to choose the right one for a...
11 min read
VFD Carrier Frequency and Switching Losses
How VFD carrier frequency trades off audible noise, IGBT switching losses, and continuous current rating, and how to pick a setting without silently derating the drive.
8 min read
Overload Relay vs MPCB vs Circuit Breaker: What Each Protects
An overload relay, an MPCB, and a molded-case circuit breaker each cover different failure modes on a motor branch circuit, and this article maps which device handles overload, short circuit,...
11 min read
In-Line vs Inside-Delta Soft Starter Connection
In-line and inside-delta are the two ways to wire a soft starter's SCRs to a motor, and the choice changes how much current the starter frame actually has to carry.
9 min read
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