USB power supply

[Geekbob]

Hi, i have a industrial USB hub that came with the 2 wire terminal block but no transformer to power it. The specs say that it can handle a 7 - 40 volt DC power supply but the company doesn't sell it with the unit nor will they tell me how to go about getting it. I am a noob at electronics but i can do basic wiring and all I need to know is what type of transformer to buy to fix this get this item powered up. Any ideas? The item is a http://ca.startech.com/Cards-Adapte...ial-SuperSpeed-USB-3-Hub-Mountable~ST7300USBM

 

[hzuiel]

I didn't find any information other than 7-40v dc on any of their spec sheets so I called startech and had a nice chat with a helpful gentleman who looked through everything they had on the product and couldn't find anything. We worked through it's power requirements and came up with some ideas, and he is going to submit a note to their tech team to revise the spec sheet and add information for the power supply requirements.

It says the power input is optional. It's only needed if the devices you're running off of it draw current from the bus, like a wireless transmitter, or usb powered speakers, etc.

Each usb port supplies 5v 900ma power, which is about 4.5 watts. 4.5 wattsx7 = 31.5 watts. A 12v 3amp ac power supply should provide about 36 watts which is more than sufficient.

It is supposed to come with a terminal for the power. Look at http://sgcdn.startech.com/005329/media/products/gallery_large/ST7300USBM.bom.jpg and note the little green terminal in the picture. You should have one of those that came with it. You can buy something like http://www.mouser.com/ProductDetail...=sGAEpiMZZMuep2RzTrr6lXHIAeQ2ADY1/7ELcmhP3tk= then snip the barrel connector end off, strip the individual wires and crimp them in those screw down terminals, and plug in. Voila.

 

[Geekbob]

Thank You. that was exactly the information i needed. I really appreciate it

 

[hzuiel]

No problem, glad to help.