Delta Elektronika SM3300 Series Product Manual page 14

INSTALLATION
5.4.7 OPTIONAL INTERFACES
 For programming via an optional interface, refer to the
interface manual for installation and cable connections.
5.5 INSULATION
 The insulation of the separating components between input
and output, such as transformers and opto-couplers, is tested
before assembly during 1 minute @ 3750 Vrms (5300VDC).
 The insulation between input and Protective Earth (3500VDC)
and between output and PE (1000VDC) is tested after
assembly.
 Note1: the specified insulation between input and output
cannot be tested afterwards on the assembled unit!
 Note2: when testing the insulation, take care to charge and
discharge the capacitors between input - case and output -
case slowly (e.g. in one second). This to prevent high peak
currents, which could destroy the power supply. Make sure to
discharge the capacitors completely before using it again.
5.6 REMOTE SENSING
 Warning! This feature is not recommended for normal use,
because damping is critical and wrong connection or routing
can lead to instabilities.
 With remote sensing, the voltage on the load can be kept
constant. The voltage drop in the load leads will be
compensated.
 Max. 2.5 V per load lead can be compensated.
 Note that the voltage drop in the leads decreases the
maximum output voltage rating: Uout = U_leads+ Uload.
 In fig. 5 - 9 it can be seen that on a 15 V unit, only 11 V will be
available on the load when 2 x 2 V compensation is used.
 To minimize the inductance in the leads of the power output,
keep them close to each other. The inductance of the load
leads could give a problem with pulsating loads.
 In this case a large electrolytic capacitor (Cd) in series with a
damping resistor (Rd) both in parallel with the load will help
(see fig. 5 - 10). Check that the capacitor Cd in combination
with the load leads and resistor Rd forms a well damped
circuit.
 Since the voltmeter is internally connected to the sensing
terminals, it will automatically display the voltage on the load.
Note that the voltage measured on the load will be lower than
on the output terminals.
 The voltage limit measures the voltage on the output
terminals, so the limit setting should be increased by the total
voltage drop in the load leads.
 For sensing on a pulsating load, see paragraph 'Special
Applications' of this chapter.
5.7 INTERLOCK FUNCTION
 The interlock connector has one output (pin1) and one input
(pin3). Pin2 is not used. As soon as the link between pin 1
and 3 is disrupted, the power output of the unit will shut down.
 If the link is open, the interlock symbol is flashing in the
display, see fig. 5 - 11 and the interlock status will be active.
 Connecting the terminals will switch the output on again.
 Warning! The terminals can only be connected to a floating
contact, for example a switch or a relay. Internally the
terminals are connected to a logic circuit which cannot be
charged or loaded!
 The current through a closed contact is less than 1mA.
 The voltage over the open contact is 3.3V (typical).
 It is not possible to connect the interlock of multiple SM3300
units in parallel.
 With regards Safety, the Interlock connector is at PE level.
 On optional interface ISOLATED CONTACTS, a floating
interlock connector is available. See chapter 7 of this manual.
 The maximum Interlock wiring length is 3 meter.
5.8 SERIES OPERATION
 The power supplies can be connected in series without
special precautions.
14 / 30 DELTA ELEKTRONIKA B.V.
fig 5 - 7
The location of the front USB-connector.
fig 5 - 8
Insulation test voltages.
fig 5 - 9
Remote sensing: voltage drop in DC load leads
subtracts from the maximum DC output voltage.
fig 5 - 10
Remote sensing on a pulsating load.
fig 5 - 11
The Interlock symbol will be visible in the display
when the link is interrupted.
SM3300
rev. Jan. 2022