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Details on installation categories and proper grounding procedures for safe operation.
Covers critical safety measures including fuse handling, input ratings, live circuits, and part substitutions.
Details on output voltage/current ranges, autoranging, display settings, and overload protection.
Instructions for connecting units in series, parallel, and master/slave configurations.
Details on analog and digital (IEEE488/RS232) programming inputs.
Instructions for connecting and using analog voltage sources for programming.
Instructions for connecting units in parallel using Master/Slave configuration.
Steps for connecting units in series using the Master/Slave adapter.
Overview of maintenance requirements, emphasizing unobstructed cooling.
Basic checks for no output, including voltage selectors, fuses, and connections.
Diagnosing and resolving programming errors and unwanted offsets.
Checking LED status and systematic steps for diagnosing serious unit failures.
The SM 700-series power supplies, including models SM 1540-D, SM 7020-D, and SM 3004-D, are safety Class 1 instruments designed for indoor use. They operate within an ambient temperature range of -20 to 50 °C, with a maximum relative humidity of 95% (non-condensing) up to 40 °C, and 75% (non-condensing) up to 50 °C. The maximum altitude for operation is 2000 m, and the pollution degree is 2.
These power supplies are designed to provide a regulated DC output voltage and current. The SM7020-D and SM3004-D models feature an AUTORANGING facility, allowing the power supply to automatically switch between two current ranges, providing a versatile output with twice the output voltage range. For the SM7020-D, 700 W of power is available at both 35 V and 70 V. For the SM3004-D, 600 W is available at both 150 V and 300 V. The voltage and current settings are not altered by AUTORANGING; only the maximum attainable current changes.
The units include a Display CV/CC Setting function, which allows users to observe voltage and current control settings on the front panel meters by pressing the Display CV/CC Setting button. This enables setting the current limit in CV mode without shorting output terminals, and the voltage limit in CC mode without opening load leads.
Overload protection is a key feature, with the power supply being fully protected against all overload conditions, including short circuits.
The input circuit incorporates a large series choke to improve the waveform, resulting in lower RMS input current, less mains distortion, and no large peak currents. An inrush current limiter and a soft start circuit ensure smooth switch-on.
The power supplies are also designed for use as battery chargers, providing constant voltage/current charging without overcharging.
Input Ratings: The power supplies have a wide input voltage range with two selectable ranges (110 V / 220 V) via a switch on the rear panel. In the 220 V position, the units can also function as a DC/DC converter. Operation at line input voltages lower than standard is possible, but with a reduction in output power.
Fuses: For 220 V operation, an 8 A slow blow fuse is used; for 110 V, a 16 A slow blow fuse. Fuses must be changed by authorized service personnel only.
Efficiency: The efficiency is very high and constant over a wide output current range, contributing to low power loss and low heat generation.
Regulation: Load regulation should be measured directly on the output terminals to avoid voltage drops across cables.
Ripple & Noise: Output ripple is very low with almost no spikes. Ripple voltage should be measured directly on output terminals using a probe with very short connections. At -20 °C, the CV ripple increases to 6/20 mV (rms/pp) for SM1540-D and 10/35 mV (rms/pp) for SM7020-D.
Programming Bandwidth: For small signals, the bandwidth is 50 Hz. For large signals, output capacitors limit the maximum slew rate. The maximum peak-to-peak output voltage swing is a function of frequency and load.
Recovery Time: For the SM7020-D at 25 °C, with a 50-100% load step and maximum output voltage, the recovery time is 100 μs. At -20 °C, the recovery time increases by 100 μs.
Noise Suppression (Input/Output): The input/output noise suppression is measured with a pulse generator. The suppression for the SM3004-D is lower, but the relative disturbance on the output is comparable to the SM1540-D.
Insulation: Insulation between input and output components (transformers) is tested at 3750 Vrms for 1 minute. Insulation between input components and the case is specified at 2500 Vrms. Insulation output to case is 600 V DC.
RFI Suppression: Both input and output have RFI filters, resulting in very low conducted RFI to the line and load, and a very clean output voltage with almost no spikes.
Operating Temperature: At full power, the operating temperature range is -20 to +50 °C. From 50 to 75 °C, the output current must be derated linearly to 20% at 75 °C.
Thermal Protection: A thermal switch shuts down the output in case of insufficient cooling. The unit will restart after cooling down. The OVP LED on the front panel will illuminate, and the OVP status output will be high.
Hold-Up Time: The hold-up time depends on load, output voltage, and line input voltage. A lighter load, lower output voltage, or higher line input voltage results in a longer hold-up time. For example, the SM1540-D at 220 VAC input and 12 V/40 A output has a hold-up time of 50 ms.
Turn-On Delay: The output voltage is available 0.5 seconds after mains switch-on.
Inrush Current: The inrush current is limited by a 50 Ohm PTC resistor, resulting in a very low current during switch-on, lower than during full-load operation.
Over Voltage Protector (OVP): The OVP protects the circuit from unwanted high voltages. It limits the output voltage to a value set by the OVP potentiometer on the front panel. The OVP LED indicates when the limit has been reached, and the OVP status output provides a logic 1 (+5 V). Recommended OVP set voltages vary by model and output range (e.g., for SM1540-D, Vout + 2 V; for SM7020-D, Vout + 3 V or Vout + 5 V depending on range; for SM3004-D, Vout + 10 V or Vout + 25 V depending on range).
Grounding: This product is a safety Class 1 instrument. The chassis must be connected to the AC power supply mains via a three or four-conductor power cable with the ground wire firmly connected to an electrical safety ground at the power outlet. For hard-wired instruments, the protective earth terminal must be connected before any other connection.
Live Circuits: Operating personnel must not remove the instrument cover. Internal adjustments or component replacements are not allowed by non-Delta Elektronika qualified personnel. Power must always be disconnected, circuits discharged, and external voltage sources removed before touching components.
Programming Inputs: Output voltage and current can be programmed by an external analog voltage (0-5 V) with high accuracy and linearity (<0.15%). A shielded cable should always be used for programming. The inputs are protected by a series resistor and parallel zener. The common is connected to the negative output terminal. Isolated programming with the ISO AMP MODULE (8-product) is recommended to prevent earth loops. Programming mode (program and manual) can be selected via switches below the programming connector.
IEEE488/RS232 Programming: The programming connector is compatible with PSC-488 and PSC-232 interfaces. Voltage and current can be programmed and read back, and CC and OVP status can be read by a computer. A shielded cable should always be used.
Monitoring Outputs: Monitor outputs provide a 0-5 V voltage proportional to the output current or voltage. These outputs are buffered by op-amps and protected by series resistors and parallel zeners.
Remote Sensing: Remote sensing keeps the voltage at the load constant by compensating for voltage drops across load leads. This feature is not available on the SM3004-D. Sense leads should be thin, shielded measuring wires, twisted, and kept close to each other to minimize inductance. Max 2 V per load lead can be compensated. The voltmeter internally connected to the sensing terminals will indicate the voltage on the load.
Series Operation: Series operation is allowed up to 600 V total voltage without special precautions. Master/Slave operation is recommended for easier control, allowing for dual tracking power supply. For series operation with the Power Sink option, all units must have Power Sink built-in.
Parallel Operation: Paralleling units has no limitations and can be done without special precautions. Master/Slave operation is recommended for easier control. Normal parallel operation of Fast Programming units may require testing with the specific load. For parallel operation with Power Sink, only one unit can have Power Sink.
Master/Slave Operation: The Master/Slave feature allows units to be combined into a larger power supply, behaving as a single unit. The autoranging feature still works in Master/Slave mode. Mixed parallel-series operation is also possible up to 600 V using the MASTER/SLAVE SERIES ADAPTER (8-product). Master/Slave parallel operation is not recommended for more than 3 units or with Fast Programming option.
Remote ShutDown (RSD): A +5 V voltage on the Remote ShutDown input (pin 5) or a relay contact will switch off the power circuit. This also causes the OVP-LED to illuminate and the OVP status to be high.
Pulsating Load: The AC component of the load current should be limited to avoid overheating output capacitors. Using a large external electrolytic capacitor in parallel with the load can decrease the AC current. When using remote sensing on a pulsating load, a capacitor between S+ and + and between S- and - with a series resistor in the sense leads filters the AC-component caused by voltage drop.
General Maintenance: The SM-series power supplies normally require no maintenance or calibration. Ensure that the cooling of the unit is not obstructed.
Cooling: Cooling is by natural convection; no noisy blowers are present. Sufficient free space (minimum 5 cm) around the unit is recommended for vertical airflow. The temperature of the air entering the unit should be below 35 °C under normal conditions, and below 50 °C under extreme conditions.
Parts Substitutions & Modifications: Only authorized Delta Elektronika service personnel are allowed to substitute parts or modify the unit. For repairs or modifications, the unit must be returned to a Delta Elektronika service facility.
Troubleshooting:
Calibration:
Spare Parts: When ordering spare parts, provide the model, serial number, component number, and component description.
General| Protection | Overvoltage, Overcurrent, Overtemperature |
|---|---|
| Output Current | 0 to 20 A |
| Ripple Voltage | 10 mV |
| Load Regulation | 0.01% + 2 mV |
| Line Regulation | 0.01% + 2 mV |
| Voltage Regulation | 0.01% + 2 mV |
| Ripple Current | 5 mA RMS |
| Input Voltage | 230 V AC ± 10% |
| Efficiency | ≥85% |
| Operating Temperature | 0 to 50 °C |
| Storage Temperature | -40°C to +70°C |
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