Power Supply

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Most Reprap electronics use 12V DC ranging from 5A-20A.

The motors plus single hotend take up to 5A or so, a heated bed typically takes 5A-15A. So for a standard setup with heated bed, look to about 18-20A total which is about 220-240W at 12V. For some setups you might be able to use less power.

There are several different options of power supply that can be used and are commonly available.

Computer PSUs

Standard PC

These provide 12V, 5V and 5V standby.

A PSU from a standard PC can be used. Some electronics have connectors for direct connection to the PSU Molex connectors, for other electronics the connectors will need to be cut and connection to stripped wires made. Some electronics can use the Power-On signal to wake up the PSU from standby.

PC power supplies vary a lot in quality, and many can not provide the rated power. A typical PC PSU can usually provide about half its rated voltage on the 12V lines, so it is best to use a power supply rated 400W or above. Otherwise the PSU will struggle to maintain 12V output. PC PSUs should have thermal overload protection, and shut down safely on overload, but again poor quality ones may not do so before overheating.

To use a PC PSU power supply, it is necessary to jumper the "power on" signal to ground, and often it is needed to supply a load on the 5V rail to get good regulation of the 12V rail.

See here for more details:

Server PSU

There are also PSUs taken from servers which can be used. These usually provide 12V only, but a LOT of current (32A), and quite cheap.

They usually have a proprietary connector designed for rack mount systems, so need some custom wiring depending on the model.

Here are instructions for HP PS-3381-1C1 400W PSUs http://www.rcgroups.com/forums/showthread.php?t=358340

Power Brick

General purpose power bricks

These come in a variety of types up to around 240W, for normal use select a 12V 220W version. Also available are 24V versions.

They often come with a barrel type or 4 pin connector. The 4 pin connector is sometimes called "mini-DIN" or "power DIN", but is not a standard DIN connector.

Also the pin assignments can vary, but for most boards you will need to cut the connector off or make an adaptor.

References: http://en.wikipedia.org/wiki/DC_connector#Snap_and_lock_DC_power_connectors

Laptop chargers

Here are instructions for converting a Dell laptop charger : http://lbmakersociety.org/2012/12/creating-hacking-a-reprap-power-supply-for-ramps/

XBOX 360 PSU

There are several versions, choose the 203W version. Note that the power may be insufficient for some heated beds. The PSU will shutdown if an overload occurs.

These provide 12V, 5V and 5V standby and power on input.

The XBOX power connector can be cut off and connections made to stripped wire, or make an adaptor with an XBOX power socket (sold as spares on eBay etc).

How to use XBOX 360 PSU with Reprap : http://www.thingiverse.com/thing:13980

OEM type PSU

These are designed to be wired into custom installations. They have exposed mains connections which should be enclosed to prevent access. It is recommended to get closed frame types, but these still have exposed mains connections.

They come in several versions, 12V or 24V and up to 400W.

The input voltage is usually universal, switchable between 110V and 220V, or sometimes fixed 110V or 220V. Check that it is compatible with your mains voltage before purchasing.

Using OEM PSU with Repap : RepRapPro_Mendel_power_supply

Suppliers

Vendors (link to product) Shipping location Manufacturer Model # (link to datasheet) Input Output(V/A) Tested Additional notes
lulzbot USA MW S-240-12 110V or 220V 12V 20A true
ebay Various HP HP PS 3381 110V or 220V 12V 32A true
ebay Various Various 12V 240W switching PSU 110V or 220V 12V 20A

See also

RAMPS_1.4#Wiring

http://en.wikipedia.org/wiki/Power_supply