The ac-mains circuit supplying power to DMS-PS-CM supplies must be fused

according to the current rating of the wire gauge used, in accordance with

applicable regulatory codes. The built-in 1ampere line fuse (F1) only protects

the module itself from destructive over currents.

5. AC Mains Connections (TB4): To ensure EMI-compliant operation, all three

ac-supply inputs must be properly connected to TB4. Never operate any DMS-

PS-CM power supply without a ground connection to TB4’s ‘FG’ terminal.

On 120Vac 50/60Hz mains, connect the black or "hot" lead to ‘AC(L)’, the

white or “neutral” lead to ‘AC(N)’, and the supply ground (earth) to ‘FG’ (Frame

Ground). On 220V 50/60Hz ac mains with line and neutral conductor-designa-

tions, connect the line to AC(L), the neutral to AC(N), and the ground to ‘FG’.

6. Connector Torque Ratings: It is extremely important to tighten all input and

output terminal blocks securely. TB4’s screw terminals must be torqued to

4.4 pound-inches (0.5Nm). TB1, TB2, and TB3 must be torqued to 3.6 pound-

inches (0.4Nm). Proper tightening will minimize losses and ensure safe,

reliable operation.

7. ‘Power On’ LED: The Power On LED indicates that the unit has ac-power

applied and its V1 dc-output is operational. However, the power-on LED’s

illumination does not imply nor guarantee that the unit’s dc-outputs are within

their specified accuracy.

8. Output Adjustment: The main output, V1, on all 5, 10, and 16W models is

adjustable by approximately –10% to +15%. V1’s adjustment potentiometer

is accessed via a small hole located next to the Power-On LED. While not

recommended, field adjustment of single-output models can be performed

within the tolerance window noted above. However, keep in mind that the

unit’s maximum output power capability must not be exceeded. For example,

increasing V1’s output voltage by 10% produces a corresponding 10% reduc-

tion in V1’s maximum output current.

On dual-and triple-output units, V1 is factory calibrated with all outputs

simultaneously loaded to 100% of their rated current. On all dual- and

triple output models, adjusting V1 under any condition other than

those just noted (i.e., all outputs loaded to their full rated current) will

adversely affect the operation and stability of auxiliary outputs V2 and

V3. On these models, V1 must be adjusted to within ±2 % of its nominal

value (+5.0V, +12.0V, or +24.0V, depending on model).

9. Temperature Derating (See Figure 3): All DMS-PS-CM supplies are speci-

fied to operate at their full rated power over the temp range of 0°C to +50°C

in still air (convection cooling) without any thermal derating. For operation

over +50°C in still air, derate the output power linearly by 2.5% per °C down

to 50% rated power at +70°C. To operate the units at full rated power between

+50°C and +70°C, a minimum forced-airflow of 100 LFM is required. For

operation below 0°C, derate the output power linearly by 2.0% per °C down

to 50% rated power at –25°C.

Unless forced air with the velocity noted above is employed, DMS-PS-CM

supplies should never be mounted upside down (terminal blocks facing

down). Also, always provide sufficient clearances in order to ensure adequate

airflow around the supply.

10. V1 Peak Capabilities: DMS-PS-CM power supplies have a maximum

continuous output-current rating that’s specified in the Ordering and Selection

Guide. In addition, each model’s V1 output can intermittently supply 120% of

its continuous rated current for short periods of time if the duty cycle is less

than 10%. Peak current ratings do not apply to the auxiliary outputs V2 or V3.

11. Isolated Outputs: Unlike the majority of competitive ac/dc power supplies,

all dual- and triple-output DMS-PS-CM power supplies feature fully-isolated

outputs. This is an important feature when, for reasons of high common mode

voltages, an instrument’s input circuit must be isolated from the system ground.

All V1 outputs are isolated from the ac mains by a minimum of 3000Vac, while

auxiliary outputs V2 and V3 are isolated from one another by 2000Vdc, and

fromV1 by 1000Vdc. The low noise, double-isolated auxiliaries are ideal for

powering sensitive instrumentation that requires low ac leakage-currents.

All ac/dc and dc/dc power components utilized in the construction of DMS-

PS-CM power supplies are 100% hi-pot tested during their manufacturing pro-

cesses. In addition, after final assembly by MPS, all models are subjected to an

additional hi-pot testing consisting of 1000Vac sequentially applied between the

ac mains input and each output, and between each output and all other outputs.

100

75

50

25

0

–25

–10

0

10152025303540455055606570

70ºC

2.5% / ºC

2.0% / ºC

75

Figure 3. Temperature Derating

DMS-PS-CM Series

High Efficiency, AC/DC Instrumentation Power

Supplies with Individually Isolated Outputs

MPM_DMS-PS-CM.B02 Page 4 of 8

www.murata-ps.com