Thurlby Thandar Instruments EX2020R User Manual [en, de, fr, it]

EX2020R

Bench Power Supply

INSTRUCTION MANUAL

Introduction

The EX2020R is an exceptionally compact and lightweight single output laboratory dc power supply providing 0 to 20V at 0 to 20A.

The EX2020R uses mixed−mode regulation technolog y which combines switch−mode pre−regulation with linear post−regulation. Special techniques are used to maintain very high efficiency whilst achieving noise levels that are close to that of a pure linear regulat or.

Excellent line and load regulation are matched by low noise and good transient response. High resolution controls allow accurate setting of voltage and current levels. Remote sense terminals are provided so that good regulation can be maintained across remote loads at high currents.

The output operates in constant voltage or constant current mode with automatic cross-over and mode indication. There is a DC output on−off switch.

The EX series incorporates separate digital voltage and current m eters on each output. The meters use bright 14mm ( 0. 56” ) LED displays and have an update rate of 4 per second providing near instantaneous response. Simultaneous metering of voltage and curr ent pr ovides accurate information “at a glance” and avoids any possibility of misinter pr etat ion. When the output switch is set to “off”, the cur r ent limit s et t ing is displayed enabling conditions to be set before the load is connected.

The EX series has been designed to meet t he s t r ingent requirements of the lates t r elevant I EC standards for safety and EMC, including harmonics emissions. All outputs are intrinsically short circuit proof, and are protec t ed against external voltages and reverse currents.

Introduction 1 Specification 10 Safety 19 EMC 28 Installation 37 Connections 41 Operation 43 Maintenance 57 Instructions en Francais 9 Bedienungsanleitung auf Deutsch 13 Istruzioni in Italiano 18 Instrucciones en Español 23

Performance levels achieved are detailed in the user manual.

EC Declaration of Conf ormity

We Thurlby Thandar Instruments Ltd Glebe Road Huntingdon Cambridgeshire PE29 7DR England

declare that the

EX2020R Bench Power Supply

meets the intent of the EMC Directive 2004/108/EC and the Low Voltage Directive 2006/95/EC. Compliance was demonstrated by conformance to the following specifications which have been listed in the Official Journal of the European Comm unit ies.

EMC

Emissions: a) EN61326-1 (2006) Radiated, Class B

b) EN61326-1 (2006) Conducted, Class B c) EN61326-1 (2006) Har m onics, referring to EN61000-3-2 ( 2006)

Immunity: EN61326-1 (2006) Immunity Table 1, referring to:

a) EN61000-4-2 (2009) Electrostatic Discharge b) EN61000-4-3 (2006) Electromagnetic Field c) EN61000-4-11 (2004) Voltage Interrupt d) EN61000-4-4 (2004) Fast Transient e) EN61000-4-5 (2006) Surge f) EN61000-4-6 (2009) Conducted RF

Safety EN61010-1 Installation Category II, Pollution Degree 2.

CHRIS W ILDING TECHNICAL DIRECTOR

2 January 2013

Voltage Range:

0V to 20V minimum

Current Range:

0A to 20A minimum

Output Voltage Setting:

By coarse and fine controls.

Output Current Setting:

By single logarithmic control.

Operating Mode:

Constant voltage or constant current with automatic cross-over.

Output Switch:

Electronic. Preset voltage and current displayed when off.

Output T erminals:

Universal 4mm safety binding posts on 19mm (0.75”) pit c h.

terminals for remote connec t ion.

Reverse protection by diode clamp for reverse currents up to 3A.

Protection:

temperature to rise excessively.

Constant current: <0.01% + 2mA

Constant current: <0.05% + 2mA

(20MHz bandwidth):

Transient Response:

<0.5ms to within 50mV of set level for a 5% t o 95% load change.

Temperature Coeff icient :

Typically < 100ppm /°C

Status Indication:

Output on lamp. Constant current mode lam p.

Meter Types:

Dual 4 digit meters with 14mm (0.56") LEDs. Reading r ate 4 Hz.

Meter Resolutions:

10mV, 10mA

Current 0.6% of reading ± 3digits

factory option. Installation Category II .

Power Consumption:

800VA max.

Operating Range:

+5ºC to +40ºC, 20% to 80% RH.

Storage Range:

−40ºC to + 70ºC.

Environmental:

Indoor use at altitudes up to 2000m, Pollution Degree 2.

Safety:

Complies with EN61010−1.

EMC:

Complies with EN61326.

Size:

140 x 160 x 320mm (WxHxD).

Weight:

3.6kg

OUTPUT

Sensing: Switchable between local and remote. Spring-loaded push

Output Protection: Output will withstand up to 25V forward voltage.

Specification

Over-temperature

Line Regulation: Change in output for a 10% line change:

Load Regulation: Change in output for any load change, rem ot e s ense connec t ed:

Ripple & Noise

METER SPECIFICATIONS

Meter Accuracies: Voltage 0.3% of reading ± 3digits,

The output will be tripped off if a fault causes t he int er nal

Constant voltage: <0.01% + 2mV

Constant voltage: <0.01% + 5mV

Typically < 2m Vrms, <20mV pk-pk, constant voltage mode.

GENERAL

AC Input: 220-240VAC ±10%, 50/60Hz; 110-120VAC ± 10%, 50/ 60Hz by

alternating current (ac )

Safety

This power supply is a Safety Class I instrument according to IEC classification and has been designed to meet the requirem ents of EN61010-1 (Safety Requirements f or Elect r ical Eq uipm ent for Measurement, Control and Laborator y Use). It is an Installation Category II instrument intended for operation from a normal single phase supply.

This instrument has been tested in accordanc e with EN61010-1 and has been supplied in a safe condition. This instruction manual contains some information and warnings which have to be followed by the user to ensure safe operation and to r etain the inst r um ent in a safe condition.

This instrument has been designed f or indoor use in a Pollution Degree 2 environment in the temperature range 5°C to 40°C, 20% - 80% RH (non-condensing). It may occasionally be subjected to temperatures between +5° and -10°C without degradation of its safet y. Do not operate while condensation is present.

Use of this instrument in a manner not spec ified by these instructions may impair the safety protection provided. Do not operate the instr um ent outside its rat ed supply voltages or environmental range.

WARNING! THIS INSTRUMENT MUST BE EARTHED

Any interruption of the mains earth conduct or inside or outside t he inst r um ent will make the instrument dangerous. Intentional interruption is prohibited. The protective action must not be negated by the use of an extension cord without a protective conductor.

When the instrument is connected to its supply, terminals may be live and opening the covers or removal of parts (except those to which access can be gained by hand) is likely to expose live parts. The apparatus shall be disconnected from all voltage sources before it is opened for any adjustment, replacement, m aint enance or repair. Capacitors inside the power supply may still be charged even if the power supply has been disconnected from all voltage sources but will be safely discharged about 10 minutes after s witching off power.

Any adjustment, maintenance and repair of the opened instrument under voltage shall be avoided as far as possible and, if inevitable, shall be carried out only by a skilled person who is aware of the hazard involved.

If the instrument is clearly def ec t ive, has been subject to mechanical damage, excessive moisture or chemical corrosion the safety protection may be impaired and the apparatus should be withdrawn from use and returned for checking and repair.

Make sure that only fuses with the required rated current and of the specified type are used for replacement. The use of makeshift fuses and the short-circuiting of fuse holders is prohibited.

Do not wet the instrument when cleaning it. The following symbols are used on the instrument and in this m anual:-

Earth (ground) terminal.

mains supply OFF.

mains supply ON.

direct current (dc)

This instrument has been designed to meet the requirements of the EMC Directive 2004/108/EC. Compliance was demonstrated by meeting the test limits of t he following standards:

Emissions

EN61326-1 (2006) EMC product standard for Electrical Equipment for Measurement, Control and Laboratory Use. Test limits used were:

a) Radiated: Class B b) Conducted: Class B c) Harm onics: EN61000-3-2 (2006) Class A; the instrument is Class A by product category.

Immunity

EN61326-1 (2006) EMC product standard for Electrical Equipment for Measurement, Control and Laboratory Use.

Test methods, limits and per formance achieved are shown below (requirement shown in brackets):

a) EN61000-4-2 (2009) Electrostatic Discharge : 4k V air, 4kV contact, Performance A (B).

EMC

b) EN61000-4-3 (2006) Electromagnetic Field:

c) EN61000-4-11 (2004) Voltage Interrupt: ½ cycle, 0%: Performance A (B);

d) EN61000-4-4 (2004) Fast Transient, 1kV peak (AC line), 0·5kV peak ( signal connections), Performance B (B).

e) EN61000-4-5 (2006) Surge, 0·5kV (line t o line), 1kV (line to ground), Perf or m ance B ( B) . f) EN61000-4-6 (2009) Conducted RF, 3V, 80% AM at 1kHz (AC line only; signal

connections <3m, therefor e not tested), Performance A (A). According to EN61326-1 the definitions of performance criteria are:

Performance criterion A: ‘During test normal performance within the specification limits.’ Performance criterion B: ‘During t est , temporary degradation, or loss of function or

performance which is self-recovering’. Performance criterion C: ‘During test, temporary degradation, or loss of f unc t ion or

performance which requires operator int er vention or s ystem r eset occurs.’

Cautions

To ensure continued compliance with the EMC directive observe the following precautions:

3V/m, 80% AM at 1kHz, 80MHz – 1GHz: Performance A ( A) and 1.4GHz to 2GHz: Performance A (A) ; 1V/ m , 2.0GHz to 2.7GHz: Performance A (A).

1 cycle, 0%: Performance B (B); 25 c ycles, 70% and 250 c ycles, 0%: Performance B (C).

a) Connect the generator to other eq uipment using only high quality, double−screened cables. b) Aft er opening the case for any reason ensure that all sig nal and g r ound c onnect ions ar e

remade correctly and that case screws are correc t ly refitted and tightened.

c) In the event of part replacement becoming nec essary, only use components of an ident ical

type, see the Service Manual.

Mains Operating Voltage

Check that the instrument oper ating voltage marked on the rear panel is suitable for the local supply.

Mains Lead

Connect the instrument to the AC supply using the mains lead provided. Should a mains plug be required for a different mains outlet socket, a suitably rated and approved mains lead set should be used which is fitted with the required wall plug and an IEC60320 C13 connector for t he instrument end. To determine t he m inimum current rating of the lead-set for the intended AC supply, refer to the power rating inform ation on the equipment or in the Specification.

Any interruption of the mains earth conduct or inside or outside t he inst r um ent will make the instrument dangerous. Int entional interruption is prohibited.

Ventilation

The power supply is cooled by a low-speed fan which vents at the rear. Take care not to rest rict the air inlets at the side panels or the exit at the rear.

Installation

WARNING! THIS INSTRUMENT MUST BE EARTHED.

Connections

All connections are made from the front panel. The load should be connected to the positive (red) and negat ive (black ) terminals marked

OUTPUT. Remote sense connections to the load, if r equired, are made from the pos it ive (+) and

negative (−) SENSE terminals. Switch the LOCAL/REMOTE switch to REMOTE when remote sensing is required. Switch back to LOCAL when remote sensing is not in use.

The terminal marked

is connected to the chassis and safety eart h ground.

Setting Up the Output

With the PO WER switch on (l) and the output off the output voltage and current limit can be accurately preset using the VOLTAGE and CURRENT controls; the left-hand met er shows the set voltage and the right-hand meter shows the set m aximum cur r ent.

Operation

When the the actual voltage and the right-hand meter t he ac t ual load current.

output switch is switched on, the ON lamp lights; the left-hand meter now shows

Constant Voltage

The output voltage is adjusted using the coar se and fine VOLTAG E cont rols; the CURRENT control sets the maximum current that c an be supplied.

Constant Current

If the load resistance is low enough such that, at t he output voltage set, a current great er than the current limit setting would flow, the power supply will automatically move into constant current operation. The current output is adjusted by the CURRENT control and the VOLTAGE controls set the maximum voltage that can be generated.

The CC lamp lights to show constant current mode.

Instantaneous Current Output

The current limit control can be set t o limit the continuous output current to levels down to 10mA. However, in com m on with all precision bench power supplies, a capacitor is connected acr os s the output to maintain stability and good transient respons e. This capacitor charges to the output voltage and short-circuiting of the output will produce a current pulse as the capacitor discharges which is independent of the current limit setting .

Protection

The output has intrinsic short-cir cuit pr ot ec t ion and is pr ot ec t ed from reverse voltages by a diode; the continuous reverse current must not exceed 3 Amps, although transients can be much higher.

Connection to the Load

The load should be connected to the positive (red) and negat ive (black ) OUTPUT terminals. Both are fully floating and either can be connected to ground.

Remote Sensing

The unit has a very low output impedance, but this is inevitably increased by the resistance of the connecting leads. At high currents this can result in significant differences bet ween the indicated source voltage and the actual load voltage (two 20mΩ connecting leads will drop 0.2V at 5 Amps, for instance). This problem can be minimised by using short, thick, connecting leads, but where necessary it can be completely overcome by using the remote sense f acility.

This requires the sense term inals to be connected to the output at the load instead of at the source; insert wires into the spring-loaded SENSE terminals and connect directly to the load. Switch the LOCAL/REMOTE switch to REMOTE. To avoid instability and transient response problems, care must be taken t o ensure good coupling between each output and sense lead.

This can be done either by twisting the leads together or by using coaxially screened cable (sense through the inner). An electrolytic capacitor directly across the load connection point m a y also be beneficial.

The voltage drop in each output lead must not exceed 0.5 Volts. Switch the LOCAL/REMOTE switch back to LOCAL when remote sensing is not in use.

Series or Parallel Connection with Other Outputs

The outputs of the power supply are fully floating and m ay be used in series with other power supply units to generate high DC voltages up to 300V DC.

The maximum permissible voltage between any terminal and earth ground ( WARNING! Such voltages are exceedingly hazardous and great care should be taken to shield

the output terminals for s uch use. On no account should the output terminals be t ouched when the unit is switched on under such use. All connections to the terminals must be made with the power switched off on all units.

It should be noted that the unit can only source current and cannot s ink it, thus units cannot be series connected in anti-phase.

The unit can be connected in parallel with others to produce higher currents. Where several units are connected in parallel, the output voltage will be equal to that of t he unit with the hig hest output voltage setting until the current dr awn exceeds its current limit s et ting, upon which the output will fall to that of the next highest setting, and so on. In constant current mode, units can be connected in parallel to provide a current equal to the sum of t he c ur r ent limit settings.

Note that the output terminals are rated at 30A maximum; if several outputs are operated in parallel to source higher currents than this the junction should be made at a separate point, not one of the terminals.

Over-temperature Protection

Sensors on both the primary and secondary heatsinks will detect over-temperature due to blocked air flow, fan failure or other circuit fault. Over-temperature will shut down the output (the display will read 0 Volts and 0 Amps if the output is ON) though the output O N lamp will remain lit. The output will remain shut down even after the heatsinks have cooled down. When the cause of the over-temperature has been r emoved and the heatsinks have cooled to normal working temperatures the output can be r eset by turning the POWER switch off (

) is 300VDC.

) then on ( l ) again.

The Manufacturers or their ag ents overseas will provide repair for any unit developing a fault. Where owner wish to undertake their own maintenance work, this should only be done by skilled personnel in conjunction with the service manual which may be purchased directly from the Manufacturers or their agents overseas.

Fuse

The correct fuse type is:

Note that the main function of the fuse is to make the inst rument safe and limit damage in the event of failure of one of the switching devices. If a fuse fails it is therefore very likely that the replacement will also blow, becaus e t he supply has developed a fault; in such circumstances the instrument will need to be returned to the manuf ac t ur er for service.

Make sure that only fuses of the required rated current and specified t ype are used for replacement. The use of makeshift fuses and the short-circuiting of fuse-holders is prohibited.

To replace a fuse, first disconnect the instrument from the AC supply. Remove the 6 cover securing screws and lift off the cover. Replace the fuse with one of the correct t ype and refit the cover.

Cleaning

If the PSU requires cleaning use a clot h t hat is only lightly dampened with water or a mild detergent. Polish the display window with a soft dry cloth.

Maintenance

10 Amp 250V HBC time-lag( T), 5 x 20mm.

WARNING! TO AVOID ELECTRIC SHOCK, OR DAMAGE TO THE PSU, NEVER ALLOW WATER TO GET INSIDE THE CASE. TO AVOID DAMAGE TO THE CASE OR DISPLAY WINDOW NEVER CLEAN WITH SOLVENTS.

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