Built-in Power Supply with High Power Density

RECOM RACM1200-V with Summit Series logo
RECOM, well-known manufacturer of AC/DC and DC/DC converters, has launched an AC/DC power supply with 1.2 kW power, the RACM1200-V. The AC/DC converter has all approvals for medical applications. RECOM developed the converter in Austria and manufactures it in Europe. The manufacturer is thus making its contribution to sustainability, as transport routes and supply chains are thus shortened.

An example of the need for a power supply with more than 1kW are robots. They are used in industry, but increasingly also in medical applications. When a robot assists the surgeon, it must move to the desired position precisely and without vibration. For this purpose, rigid robot arms are used, which are moved by high-torque stepper motors. The motors have a correspondingly high power consumption. For hygienic reasons alone, fans are taboo in the operating theatre. The power supply units must be base-plate cooled. And they must meet higher insulation requirements such as IEC/EN or ANSI/AAMI 60601-1 (3rd edition), i.e. higher requirements than for industrial use. A power supply certified for medical use can be used in industrial applications - but not vice versa.
Precision robotic arm in lab
Fig. 1: Cobot for medical use
If the power supply unit is used to supply devices that are used directly on the patient, they must have double insulation and double creepage distances. They must comply with the so-called 2xMOPP insulation. "The safe option is the only option" is the principle that RECOM has consistently applied to the RACM1200-V. The RACM1200-V already has all the approval tests required for medical use.

The RACM1200-V operates in a wide power range without a fan and has a remarkably compact design that sets new standards. A special base plate allows heat dissipation up to a continuous power of 1000W. Two additional outputs replace additional power supplies in many applications. One output is adjustable from 5V to 12V and can supply a fan, for example. The second output supplies 5V/1A and also works in the standby mode of the power supply unit.

The high insulation strength of 4kV(AC) between the mains voltage and the output voltages allows the RACM1200-V to be used in almost all areas where a power supply unit is required. These can be chargers or LED lighting, but also laser devices, analysis devices, high-frequency devices, robots or medical beds and chairs, right up to medical devices that are used directly on the patient. Thus, developers of the devices mentioned have a power supply unit at their disposal that already meets the required specifications. Although the fully IEC 60601-1 certified power supply unit does not yet guarantee compliance with IEC 60601-1 for the entire unit, it is a prerequisite. This is very helpful for a smooth certification process of the final product and saves development costs.

The units are designed to ensure 2xMOPP (Means of Patient Protection) insulation. These patient protection measures, together with the low leakage currents, guarantee that medical safety standards can be met. The signal outputs and the 5V output have 1.5kV(AC) isolation to the mains voltage.

The series is launched with built-in EMC filtering that has sufficient Class B clearance for radiated and conducted disturbances. It meets the international safety standards for industrial applications, for information technology products and for medical devices.

Variety of RECOM RACMx AC/DC converters
Fig. 2: The RACMxx series of medically certified power supplies, from left to right: 230W, 550W and 1200W

One AC/DC converter with 1200W is sufficient for many applications and can advantageously replace several smaller converters. The operating power of a single high-power AC/DC converter is higher than that of several smaller converters. Each power supply has an internal power consumption, which is kept as low as possible, but the internal consumption still adds up with multiple power supplies. For example, if an equipment rack contains twelve individual 100W power supplies, each with 2W of internal consumption, the total losses add up to 24W. In comparison, a large converter has only 2W losses. If the gear tray runs continuously, around 200 kWh can be saved per year. The RACM1200-V has a no-load power consumption of 0.75W (main output off, auxiliary output still active). It meets the efficiency requirements "80 Plus Platinum" and "Ecodesign Lot 6".

The input voltage range is from 85VAC to 264VAC. The RACM1200-V delivers the 1000W output power in a metal housing with contact cooling that has a footprint of only 102mm x 229mm and is 40mm high. Over the duration of 10s, the output power may even be 1200W. For a constant output power of 1200W, however, a fan is needed that blows the air through the enclosure at 2.5m/s. The fan can be controlled by the user. A controllable additional output is available for this purpose, which allows the temperature management to be adjusted.

Key data of the RACM1200-V

Output power: 1000W at 40°C ambient temperature and 230V input voltage, 1200W with fan or for short-term peak loads.
Dimensions, including connections (LxWxH): 228.0mm x 96.2mm x 40.0mm, with other manufacturers the connection area is mechanically exposed.
Power density: Power density equation
Efficiency: 95% see figure 2
Power factor: See figure 3
Efficiency vs. output power graph
Fig. 3: Efficiency curve
Power factor vs. output power graph
Fig. 4: Power factor
Weight: 1kg typical
Input voltage: 85V to 264V
Output voltage:
  • The 24V version can be adjusted to a maximum of 28V in 100mV steps with dip switches.
  • The 48V version can be adjusted to a maximum of 56V in 200mV steps with dip switches.
Maximum output current: 50A@24V, 25A@48V
Protection functions for main output and auxiliary voltages:
  • Overvoltage, automatic reset
  • Overcurrent and short circuit with automatic reset
  • Overtemperature, automatic restart
Temperature range: -40°C to 80°C, derating from 50°C up, see data sheet
Lifetime at 40°C ambient temperature: 88000 hours
Ripple of the output voltage, maximum: 1% of the output voltage
Output voltage tolerance: 1% typ.@25°C, ± 2% maximum above temperature
Certified according to: IEC/EN 62368, UL/IEC/EN 60601
Conformity to: IEC/EN 61558-2-16, IEC61010-1 and OVC III to IEC62477-1 up to 2000m
Cooling via: aluminium base plate or with fan
Operation above sea level: maximum 5000m (IEC/EN62368-1), 4000m (IEC/EN60601)
Additional output voltage: 5V/1A, isolated
Standby consumption: <1W (eco-design)
LED display of operating states: not only convenient, but also contributes to safety
Remote on/off: TTL input
AC okay: Open collector output
PSU-good: Open collector output
PSU-good: Open collector output pin; power supply unit works, output voltage okay, temperature in acceptable range, no internal error. Serves for safety, reliability and quality.
Maximum leakage current across the patient: 100μA at N.C. (normal situation) and 500μA at S.F.C. (one-fault case).
Medical protection class: 2xMOPP
Precisely adjusted output voltage: To control the voltage drops on the lines, "remote main-output voltage sensing" has been implemented, whereby the output voltage is measured and controlled at the desired point via two additional (sense) lines. This eliminates the voltage drops on the lines where the large currents (25A/50A) flow. Activation is via 2 TTL inputs (5V).

Power supply schematic showing PE, VAC inputs and Vout

Fig. 5: Remote sense for the main output voltage
Applications
  Series
1 AC/DC, 1200.0 W, Single Output, Connector RACM1200-V Series
Focus
  • Up to 1000 Watt fan-less power / 1200W boost
  • Designed and manufactured in europe
  • Efficiency exceeding 90% from 15% load
  • Wide Operating temperature range -40…+80°C