The Mean Well RT-125B is a multi-output enclosed switching AC-to-DC power supply that provides 5V @ 12A, +12V @ 5A and -12V @ 1A.
- Mean Well RT-125B Power Supply
KEY FEATURES OF MEAN WELL RT-125B POWER SUPPLY:
- Fully enclosed, convection cooled
- Multiple outputs of 5V @ 12A, +12V @ 5A and -12V @ 1A
- 132W total power with good regulation
- Screw terminal block connections
- High quality, UL approve
The RT-125B power supply is fully enclosed in a metal enclosure and is convection cooled, so there is no fan to attract dust, make noise or fail. There is a green LED power indicator when AC power is applied.
Depending on how much total power is being drawn from the supply, each of the outputs has the ability to provide a little more current and can go up to a max of 5V @ 15A, +12V @ 6A and -12V @ 1A, just not all at once.
Multi-output power supplies have a minimum load requirement in order for the supply to properly regulate. If the power supply is powered up with no load connected, the green LED will blink on/off and a clicking may be heard because the supply is not regulating. We find that the 5V output needs about a 250 mA load for things to settle down, but please refer to the datasheet in the link in the Specifications section for full details.
Note before first using the power supply:
There is an AC Input Voltage Selector Switch visible and accessible through the perf holes on the side of the enclosure. Ensure that this is set to the voltage that you intend to use (115VAC or 230VAC) before power is applied. A small screwdriver or similar tool can be used to slide the switch through the openings without removing the cover. There is a warning label to alert you to set the switch on top of the power supply not shown in these pics. We preset this to 115V since that is what most customers will use.
The 5V power output is preset for a nominal 5V output.
A small voltage adjustment potentiometer +5V ADJ near the power LED can be used to adjust the output voltage over the range of 4.75V to 5.5V if desired. This can be useful when compensating for a voltage drop when using long power leads.
The ± 12V outputs are fixed and cannot be adjusted.
Connections are made using 7mm wide screw terminals.
- L = AC Line (hot)
- N = AC Neutral
- Gnd Symbol = AC / Chassis Ground
- NC = No Connection
- V3 = -12V Output
- +V2 = +12V Output
- COM = Common / Ground
- +5V = 5V Output
There are 2 mounting holes accessible from the top of the unit as well as 4 M3 PEMs on the bottom and 3 M3 PEMs on one of the sides which can be used for mounting as well.
OUR EVALUATION RESULTS:
Mean Well power supplies are good quality robust units offered at a fair price. They are probably the best price / performance value power supplies available and they are fully UL and CE safety certified.
The ventilated enclosure allows for good convection cooling and provide a little more safety margin than when using open frame supplies.
- Multi-output power supplies have a minimum load requirement in order for the supply to regulate. If the power supply is powered on with no load connected, the green LED will blink on/off because the supply is not regulating. Please refer to the datasheet in the link below for the details.
|Output||DC Voltages||+5V / +12V / -12V|
|Rated Current||12A / 5A / 1A|
|Noise / Ripple (max)||80mV / 120mV / 120mVp-p|
|Adjustment Range (5V)||4.75 – 5.5V|
|Input||Voltage Range||88 – 132 / 176 – 264VAC @ 47 – 63Hz
|Protection||Overload||110 – 150% rated power, hiccup mode|
|Working Temp||-40°C ~ +85°C|
|Dimensions||209 x 98 x 33mm (8.2 x 3.9 x 1.3″)|