Melcher W Series 125, 250 Watt AC-DC and DC-DC DIN-Rail Converters Convert Select LWN2660-6E-G

Features

• RoHS lead-free-solder and lead-solder-exempted products are available 

 • Rugged 35 mm DIN-rail snap-fit design 

 • Class I equipment 

 • Universal AC-input or DC-input (66 – 150 or 90  – 350 VDC) with single stage conversion 

 • Power factor correction, harmonics IEC/EN 61000-3-2 

 • Virtually no inrush current 

 • Compliant with EMC standards EN IEC 61204-3,   EN 50121-3-2 

 • Emissions according to EN 55011 / 55032 

 • Very high efficiency; up to 89% 

 • Short-term output peak power capability, rectangular current limiting characteristic 

 • Single or two independently regulated outputs with   12, 24, 36, or 48 V 

 • Outputs no-load, overload, and short-circuit proof 

 • PCBs coated by protective lacquer 

 • Very high reliability

Description

The MELCHER Convert Select series represents a family of DIN-rail mountable DC-DC and AC-DC converters with power factor correction. The converters have been designed according to the latest industry requirements and standards. The converters are ideal for use in outdoor and other demanding applications to power building control systems, factory automation, industrial controls, instrumentation, electromagnetic drives, fans, and other DC loads. Different models are available with a single output or two independently regulated, electrically isolated outputs with 12, 24, 36, or 48 V. Special models for battery charging are available. The EW models are particularly suitable for 110 V railway applications; they have been designed in accordance with the railway standards EN 50155 and EN 50121. Key features of the Convert Select line include power factor correction with low harmonic distortion, negligibly low inrush current, high immunity to transients and surges, and low electromagnetic emissions. Internal protection circuits such as input over- and undervoltage lockout, thermal protection, as well as output overvoltage protection by a second control loop ensure safe operation of the final system. The outputs deliver an electrically-isolated Safety Extra Low Voltage (ES1) and low output noise. They are no-load, overload, and short circuit proof. The electronically controlled short-term peak power capability of up to 150% of the rated output power enables the front end converters to deliver additional power to start-up motors or to safely operate subsequent circuit breakers. Built-in large sized output capacitors absorb possible reverse energy, which may be caused by quick deceleration of electromagnetic drives connected directly to the output. A green LED at the front cover displays the status of the output(s). The Convert Select Series was designed according to all relevant international safety standards. The converters are approved by Nemko and CSA and are UL 508 listed. Adequate clearances and creepage distances allow operation in pollution degree 3 environment (with AC input). All board assemblies are coated with a protective lacquer. The thermal concept allows operation at full load up to an ambient temperature of 60 °C (LW models) or 70 °C (EW models) in free air without forced cooling. A rugged DIN snap-fit device allows easy and reliable fixing onto the various 35 mm DIN rail models. The converters are fitted with cage clamp terminals which are easily accessible from the front. System connectors with screw terminals for use with pre assembled harnesses, external adjustment of the output voltage as well as various auxiliary functions are available as options. The letter E stands for improved EMC performance of LW models. Models without E are obsolete.

Product Marking

 Basic type designation, applicable safety approval and recognition marks, CE mark, warnings, pin designation, company logo.

 Specific type designation, input voltage range, nominal output voltages and currents, degree of protection, batch number, serial

number and data code including production site, version, and date of production.

Functional Description

The W Series converters are primary controlled AC-DC or DC-DC flyback converters with a constant switching frequency of 130 kHz.The power-factor-corrected single-step con version of the input voltage to a low output voltage results in extremely high efficiency.Depending upon the output power, the converters are fitted with one (125 W) or two (250 W) powertrains. Models with two powertrains have one or two outputs. Double-output models exhibit individually regulated power trains.

 The input voltage is fed via fuse, filter, and rectifier to the main transformer, designed in planar technique. The input filter with very small input capacitance generates virtually no inrush current. An input transient suppressor protects the converter against high voltage peaks and surges. Input over- and undervoltage lockout as well as input current limitation protect the converter from operation outside of its specification. The input voltage waveform is sensed by the primary control logic to allow active power factor correction,forcing the input current to follow the input voltage waveform.  

The secondary side of the main transformer supplies via the rectifier diode a large electrolytic output storage capacitor providing for the hold-up time. Double-output models exhibit an individual control logic each. The output voltage and the output current are measured and fed back to the primary control logic via an optocoupler. A second control loop monitors the output voltage. It disables the output in the case of a failure in the control logic and limits the output voltage. Built-in temperature sensors monitor the internal temperature of each powertrain. If the temperature exceeds the limit, the converter reduces the output power continuously to keep the temperature below its limit. A green LED on the front cover confirms the presence of the output voltage(s).  

The R input (option R, M1, or M2) allows for external adjustment of the output voltage by means of a resistor or an external voltage source. An external sensor can be connected to the R input and allows for temperature-controlled battery charging (see Accessories). 

Output Power Derating

The output power of LW models must be decreased at low input voltage and/or powertrain temperature above 125 °C.

The powertrain temperature depends on the output power, the input voltage, and the cooling method. At low input voltage the losses increase. At the maximum specified environment temperature TA free air convection cooling might be insufficient approaching maximum ambient conditions. As a result, the output power has to be reduced according to the tables below.

Note: The measurements have been made by the approval boards with free air convection cooling according to 62368-1 3rd edition specified ambient temperature TA and with the converter built in a cardboard box according to UL 508 and a specified temperature outside the box Tout .

The tables give a correlation between TA or Tout and the case temperature TC (measuring point TC see Mechanical Data). For models not specified, please contact the Company

EW models need no derating.

Input Fuse and Protection

A fast-blow fuse (Schurter F 6.3A, 5 × 20 mm), protected by a sleeve, is connected to the input L [W/V]-0.67-1.25-0.67-1.25 or Vi+. EW models have a smaller fuse (250 V, 4 × 9 mm, SOC NT3 6.3A V009, UL-recognized E-39265). For DC input voltages above 250 V consult the Installation Instructions.

Converters with option F have large fuses (F6.3A, 5 × 20 mm). The DC input voltage for converters with option F is limited to 250 V. A VDR and a symmetrical input filter form an effective protection against input transients.

An under- and an overvoltage lockout protect the converter, which is disabled below Vi min and above Vi max by an internally generated inhibit signal.

The built-in bridge rectifier (LW models) provides reverse polarity protection at the input if operated from DC. EW models are protected by the (blowing) input fuse in connection with the body diode of the main transistor. Option Q offers a serial diode, but this reduces the efficiency by approx. 1%.

Parallel Operation

Double-output models exhibit an independent control logic each. Both outputs can be con nected in parallel, provided that options S (included in M1) and R are not used, since they influence only the 2nd output. The two power trains share the current due to their output voltage droop characteristic.

Up to 3 converters with the same output voltage may be operated in parallel. It is possible to parallel W Series with X Series converters.

Reasonable current sharing is achieved by the droop characteristic. Correct mode of operation is highly dependent upon the wiring of the converters and the impedance of these wires. Use wires with equal length and equal cross sections of min. 1.5 mm2. The best results for parallel operation can be achieved with the wiring shown in fig. 6.

Parallel operation of single-output models using the option R (output voltage adjust) is possible, but not recommended.  Refer to f ig. 6; the connections between the pins 8 and 9 (both Vo–) should be as short as possible.

Note: Parallel operation is not possible, if a temperature sensor is connected, as the sensor eliminates the output voltage droop. 

Note: For ORing diodes, we recommend to use Schottky diodes, mounted on a common heatsink to avoid thermal run away (or the use of double diodes).

Output Characteristic and Protection

The output characteristic, individual for each powertrain, is rectangular with a droop to ease parallel operation; see fig. 7. However, a 50% higher output current is possible for a short time, such allowing start-up of loads or charging of capacitors; see fig. 8. Each output is independently protected against internal overvoltage by means of a second control loop. When the output voltage exceeds Vo L , the respective output is disabled.

Overtemperature Protection 1.4 1.6 1.2 1.0 0.8 0.6-- 0.5 0.5 1.5  2.5  s Io / Io nom 05194b 0 1 2 Fig. 8 Short term peak power characteristic: overcurrent versus time (typical values). A built-in temperature sensor protects each powertrain is independently protected against over temperature. When a certain temperature is reached, the concerned powertrain reduces its output power continuously. Thermal Considerations The thermal conditions are influenced by input voltage, output current, airflow, and temperature of surrounding components. TA max is therefore, contrary to TC max , an indicative value only. Caution: The installer must ensure that under all operating conditions TC remains within the limits stated in the table Temperature specifications. Note: Sufficient forced cooling allows TA to be higher than TA max provided that TC max is not exceeded. It is recommended that continuous operation under worst case conditions of the following 3 parameters be avoided: Minimum input voltage, maximum output power, and maximum temperature. Battery Charging and Temperature Sensor The battery charger models exhibit the option M1 and have been designed to charge lead-acid batteries. The R-input allows for connecting a battery-specific temperature sensor, which provides temperature controlled adjust of the trickle charge voltage. This optimizes charging as well as battery life time. Depending upon the cell voltage and the temperature coefficient of the battery, different sensor types are available; see Accessories. Note: Parallel operation is not possible, if the temperature sensor is connected to the paralleled outputs Vo+, as the sensor eliminates the output voltage droop. However, it is possible to insert bleeding resistors in the Vo+ output lines of each converter in order to create a droop of approx. 0.6 V @ Io nom for 24 V outputs (1.2 V @ Io nom for 48V outputs), but this creates considerable power losses.

Installation Instructions

The converters of the W Series are components, intended exclusively for inclusion within other equipment by professional installers. Installation must strictly follow the national safety regulations in compliance with the enclosure, mounting, creepage, clearance, casualty, markings and segregation requirements of the end-use application.

DIN-rail mounting is possible with the built-in snap-fit device on a DIN-rail. This fulfills the mechanical transport re quirements as per ETSI 300019-1-2, class 2 (vertical). To fulfill the requirements of IEC 721-3-2, class 2.1 (vertical), 2 additional fixing brackets HZZ00624-G (see Accessories) must be fitted on the bottom side of the DIN-rail. For heavy duty railway applications, we recommend installing all 4 fixing brackets HZZ00624-G.

Chassis or wall mounting is possible using the universal chassis-mounting brackets HZZ00618-G (see Accessories). Such installa  tion complies with IEC 721-3-2, class 2.2 (vertical and horizontal).

Caution: Install the converters vertically, and make sure that there is sufficient airflow available for convection cooling. The minimum space to the next device should be: top/bottom: 30 mm, left/right: 20 mm.

The converters of the W Series are class I equipment: Input terminal 1 ( ) and the output terminals 1 and 11 ( connected to the case. For safety reasons it is essential to connect the input terminal 1 ( ) are reliably ) with protective earth. Output terminals 1 and 11 can be used to connect the output voltage(s) or the load to functional earth.

The phase input (L or Vi+) is internally fused; see Input Fuse. This fuse is de signed to break an overcurrent in case of a malfunction of the converter and is not customer-accessible. External fuses in the wiring to one or both input lines (L and/or N ) may be necessary to ensure compliance with local requirements. A built-in second fuse in the neutral path is available as option F. A second fuse in the wiring to the neutral terminal N or option F is needed if: 

 • Local requirements demand an individual fuse in each source line 

 • Neutral and earth impedance is high or undefined 

 • Phase and neutral of the mains are not defined or cannot be assigned to the corresponding terminals (L Models with Option F: Caution! Double-pole/neutral fusing. to phase and N to neutral). If the converters operate at source voltages above 250 VDC, an external fuse or a circuit breaker at system level should be installed. Caution: 

 • Installation must strictly follow the national safety regulations.

 • Do not open this apparatus

Standards and Approvals The converters of the LW Series with feature E were safety-approved to IEC/EN 62368-1 3rd edition and UL/CSA 60950-1 2nd edition (models without E: IEC/EN 62368-1 3rd edition), IEC 61010-1:C11:2002 (models without E: IEC 61010-1), and EN 50178:1997 (with and without E). The converters are UL508-listed components. The EW models are safety-approved to IEC/EN 62368-1 3rd edition and UL/CSA 60950-1 2nd edition The converters have been designed in accordance with said standards for: 

 • Class I equipment 

 • Power supply for building-in, vertical mounting on 35 mm DIN-rail or on a wall 

 • Overvoltage category II (III for 110 VAC supply) 

 • Basic insulation between input and case, based on 250 VAC 

 • Double or reinforced insulation between input and output, based on 250 VAC and 350 VDC. 

 • Functional insulation between outputs and case. 

 • Functional insulation between outputs. 

 • Pollution degree 2 environment. The converters are subject to manufacturing surveillance in accordance with the above mentioned standards and with ISO9001:2015. Operation at Frequencies Greater 60 Hz The LW Series converters have been tested for operation up to 440 Hz. However, the Y and X caps are not approved to such frequency. The leakage currents are higher than at 60 Hz, whereas the output ripple voltage is lower. Leakage Currents with AC Supply Leakage currents flow due to internal leakage capacitance and RFI suppression Y-capacitors. The current values are proportional to the mains voltage and nearly proportional to the mains frequency. They are specified at maximum operating input voltage where phase, neutral, and protective earth are correctly connected as required for class I equipment. Leakage current may exceed 5 mA, if f i > 63 Hz. Railway Applications The W Series converters have been designed observing the railway standards EN 50155 and EN 50121. All boards are coated with a protective lacquer. The EW Series is particularly suitable for connection to 110 V railway batteries. Isolation The electric strength test is performed in the factory as routine test in accordance with EN 62911 and IEC/EN 62368-1 3rd edition and should not be repeated in the field. The Company will not honor warranty claims resulting from incorrectly executed electric strength field tests.

Safety of Operator-Accessible Output Circuits 

 If the output circuit of a converter is operator accessible, it shall be a ES1 circuit according to 62368-1 3rd edition related safety standards. The converters have ES1 output circuits up to an output voltage of 57.5 V. However, if the isolated outputs are connected to another voltage source or connected in series with a total of >57.5 V the outputs are hazardous. It is the sole responsibility of the installer to ensure the compliance with the relevant and applicable safety regulations.