Delta Elektronika M 24-12 HE User manual

M24-12 HE

M24 - 20 HE

M - SERIES
LINEAR POWER SUPPLIES WITH HIGH EFFICIENCY AND HIGH RELIABILITY
The M-series has proved to be one of the most reliable series of modular power supplies. Many thousands are being
used without any problems for more than 25 years. According to our statistics over many years the average number of
repairs is less than one per thousand per year, including faults caused by wrong use. The circuits of these linears are
very simple compared with the complexity of switchers. The number of components is only a fraction of that of a
switcher. Moreover the components are very reliable.
The disadvantages compared with switchers are the relatively larger weight and dimensions and a lower efficiency.
The M-series modular power supplies are designed for use at a fixed output voltage. The M15-16 HE for 15 V 16 A has a
tap point on the transformer secondary so that it can also be used at 12 V 16 A. In the same way the M 60-5 HE can also
be used at 48 V 5 A.
Model Vout Iout Efficiency Size
M15 -16 HE 12 V / 15 V 16 A 70 % half rack
M24 -12 HE 24 V 12 A 74 % half rack
M60 -5HE 48 V / 60 V 5 A 75 % half rack
M24 -20 HE 24 V 20 A 74 % full rack
M48 -10 HE 48 V 10 A 75 % full rack
Some features are:
*Extra output terminal via a built-in diode for use in redundant operation
*Built-in adjustable overvoltage protection (crowbar type)
*Very low output ripple
*Fast response to load transients
*No generation of RFI
*It withstands the high energy impulse test 2.3 ÛN1.3 ms of VDE 0160
*Split bobbin transformer
half rack full rack
DELTA ELEKTRONIKA B.V.
P.O. Box 27
4300 AA Zierikzee
The Netherlands
Tel. [phone]
Fax. [phone]
www.deltapowersupplies.com

DELTA ELEKTRONIKA BV M - SERIES
Page 1 - 4Febr. 2005
SPECIFICATIONS
Input voltage
110 - 120 - 230 - 240 V 48/62 Hz
(by changing transformer taps).
Input current (230 V)
Half rack model 2.2 A, full rack 3.5 A
Fuses, 5 x 20 mm, slow blow
Half rack: 4 A T at 230 V, 6.3 A at 110 V
Full rack: 6.3 A T at 230 V, 10 A at 110 V
Power factor 0.8
Insulation
Input to output: 4 kV RMS
Input to case: 2500 V RMS
Output to case: 500 V DC
The transformer has a split bobbin according to VDE
0551, CEE 15 which makes the unit very safe.
Safety EN 60950, EN 61010
SELV/PELV (for M15-16HE, M24-12HE,
M24-20HE)
EMC
EN 61204-3
EN 61000-6-3 (EN55022B)
EN 61000-6-2
VDE 0160 impulse test
The M-units withstand the high energy impulse test
2.3 ÛN1.3 ms of VDE 0160 class 2
Hold-up time (230 V input)
24 V units 20 ms at full and 50 ms at half load. Other
models 15 ms at full and 30 ms at half load.
Voltage regulation
0.02% for a +10% to –10% line variation.
0.02% for a 0-100% load change.
Ripple + noise
0.2 mVrms (BW = 300 kHz)
5 mVp-p (BW = 50 MHz)
Temperature coeff.
0.01% per °C
Drift
Less than 0.1% per 8 hours under constant ambient
and load conditions after 1 hour warm-up.
Output impedance
Less than 0.1 Ohm at 0 to 100 kHz load frequency.
Recovery time
25 us for recovery to within 30 mV of steady state volt-
age after a step load change from 10% to 100%. Max.
deviation: Less than 0.25 V
Recovery time:
M 24-12 HE
Hor.: 100 us/div.
Vert.: 0.1 V/div.
Current limit
The linear M-models
have a fold back overload characteristics (a constant
current characteristic would overheat the series pass
transistors when the output is short circuited).
A ‘delayed fold back’ is used to avoid problems during
switching-on of series connected power supplies or
non linear loads. The cur-
rent limit is adjustable from
about 40 to 100% of the
rated current.
Remote sensing
Remote sensing at the load
point can be used to com-
pensate for the voltage
drop across the load leads.
Max. 2 V per load lead can
be compensated. The voltage across the output will
rise accordingly, which will limit the max. AC input
voltage swing (check graphs on next page). Also the
OVP has to be set higher. The output is protected
against accidental interruption or reversing of the
sense leads.
A capacitor of 1000 uF across the load can be usefull
to lower the impedance caused by long load leads.

M - SERIES DELTA ELEKTRONIKA BV
Febr. 2005 Page 1 - 5
Efficiency
The 70 to 75% efficiency of the M series is high for linear
power supplies. The power supplies are dimensioned
to stay within regulation down to 198 V AC input. How-
ever if the line voltage is already stabilized and never
drops below 215 V, the input can be connected to the
240 V tap of the transformer. This will still increase the
efficiency of the M 24-20 HE from 74 to 79%, saving
considerable heat.
Parallel operation
With parallel operation the current will not be shared
equally but the current limit of each unit will avoid over-
loading. The current sharing is better if the load wires
are of equal length and the outputs adjusted at equal
voltages. To do this a multimeter can be used to mea-
sure the difference of the output voltages. Remote
sensing is not recommended with parallel operation.
To enable parallel operation at higher ambient temper-
atures the current limit of all units can be set lower. At
parallel operation without separation diodes, the OVP
has to be turned out of range (high) because it is only
rated for one power supply.
Parallel operation for redundancy
For redundant parallel operation an extra positive out-
put terminal via a built-in diode is available.
Remote sensing cannot be used.
Redundant parallel operation
Parallel operation
Output voltage adjustment range
The M-series is meant for use at a fixed output
voltage. However it can be used over a larger
range at a lower output current or with a smaller
AC input variation (see graphs). The adjustment
ranges are given below.
M 24-12 HE 24 - 28 V
M 24-20 HE 24 - 28 V
M 48-10 HE 48 - 54 V
M 15-16 HE
if connected for 12 V: 12 - 14 V
if connected for 15 V: 15 - 17 V
M 60-5HE
if connected for 48 V: 48 - 54 V
if connected for 60 V: 60 - 64 V
The M 15-16 HE has a tap on the transformer sec-
ondary for use at 12 V instead of 15 V. To avoid
overheating of the series pass transistors it is very
important not to forget to connect it to the lower tap
when turning down the output to 12 V. The same
applies for the M 60-5 HE for 60 and 48 V.
Maximum output at
reduced
AC input voltage

DELTA ELEKTRONIKA BV M - SERIES
Page 1 - 6Febr. 2005
Series operation
Series operation is allowed up to 500 V total volt-
age.
Overvoltage protector
Built-in OVP shorting the output in case of
overvoltage. Adjustable up to 8 V above the output
voltage range.
Undervoltage alarm
Built-in P366 is optional.
Cooling
Natural convection cooling.
Sufficient space has to
be kept above and below the
unit to permit a vertical airflow.
Ambient temperature
– 20 to + 50 °C at full output. From + 50 to + 75 °C
the output current has to be derated linearly to
20% at 75 °C.
Rack mounting
Two half-rack units can be rack mounted with the
help of 2 brackets H7. Empty half rack modules
are available, ordering code M 1/2.
Wall mounting of half rack units
Dimensions and weight
Half rack (h x w x d):
132.5 x 206 x 260 mm 8.8 kg
Full rack (h x w x d):
132.5 x 412 x 260 mm 16.0 kg
Perforated covers
CM1, set of 2 for M 24-12 HE
CM2, set of 2 for 2 pcs M 24-12 HE
A half rack unit can be wall mounted with two
brackets H7 (without grip).
MTBF
1000 000 hrs
Optional
Built-in undervoltage alarm P366.

Safety Instructions
Caution.
The following safety precaution must be observed during all phases of operation, service and
repair of this equipment. Failure to comply with the safety precautions or warnings in this document
violates safety standards of design, manufacture and intended use of this equipment and may
impair the built-in protections within.
Delta Elektronika shall not be liable for user’s failure to comply with these requirements.
Installation category.
The Delta Elektronika power supplies have been evaluated to installation category II.(Over voltage
category II)
Grounding
This product is a safety Class 1 instrument. To minimize shock hazard, the instrument chassis
must be connected to the AC Power Supply mains through a tree or four conductor power cable for
resp. a single or three phase unit, with the ground wire firmly connected to an electrical ground
(safety ground) at the power outlet.
For instruments designed to be hard-wired to supply mains, the protective earth terminal must be
connected to the safety electrical ground before another connection is made. Any interruption of
the protective ground conductor, or disconnection of the protective earth terminal will cause a
potential shock hazard that might cause personal injury.
Fuses
Fuses must be changed by authorized Delta Elektronika service personnel only, for continued
protection against risk of fire.
Input Ratings
Do not use an AC Supply which exceeds the input voltage and frequency rating of this instrument.
The input voltage and frequency rating of the Delta Elektronika power supply series are stated in
de accompanying datasheet.
Live circuits
Operating personnel must not remove the instrument cover. No internal adjustment or component
replacement is allowed by non Delta Elektronika qualified personnel. Never replace components
with the power cable connected. To avoid injuries, always disconnect power, discharge circuits and
remove external voltage sources before touching components.
Parts Substitutions & modifications
Parts substitutions and modifications are allowed by authorized Delta Elektronika service personnel
only. For repairs or modifications the unit must be returned to a Delta Elektronika service facility.

Environmental Conditions
The Delta Elektronika power supplies safety approval applies to the following operating conditions:
Indoor use
Ambient temperature : -20 to 50 °C
Maximum relative humidity : 95%, non condensing, up to 40 °C
: 75%, non condensing, up to 50 °C
Altitude: up to 2000m
Pollution degree 2
Caution risk of electrical Shock
!
Instruction manual symbol. The instrument will be marked with this symbol when it is
necessary for the user to refer to the instruction manual
Protective ground conductor terminal
o Off (supply)
I On (Supply)
WEEE
(Waste Electrical & Electronic Equipment)
Correct Disposal of this Product
Applicable in the European union.
This marking shown on the product, its packing or its literature indicates that
it should not be disposed with other wastes at the end of its working life, but
should be collected separately to recycle it responsibly to promote the
sustainable reuse of material resources.