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HB-25 question — Parallax Forums

HB-25 question

legoman132legoman132 Posts: 87
edited 2010-06-09 17:01 in Robotics
Hello everyone,
I am building my own ROV and I need to control a group of motors with a combined draw of just under 11 amps at 12 volts. I know a stock HB-25 could handle this, but I was wondering how much continuous current an HB-25 could handle without the fan (i was considering moving it to a vent hole on the electronics casing to help keep the other motor controller and the propeller cool if it could handle the current without it.

Thanks!

Comments

  • hover1hover1 Posts: 1,929
    edited 2010-06-08 01:33
    It is always unadvisable to dissect a pre-engineered part and expect it to work out of it’s tested conditions. I don’t think Parallax would comment on it. It would also void the warranty.

    Do you have an alternative to provide the proper cooling?

    Jim
  • legoman132legoman132 Posts: 87
    edited 2010-06-08 01:51
    Ya i have some other fans i can get to work, but thanks for responding so fast
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2010-06-08 06:21
    Interestingly the HB-25 was tested at maximum current without the fan. The heatsink got hot, but it never overheated. That said, we don't condone modifying the product and cannot warranty it if it fails under those circumstances. [noparse];)[/noparse]

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    Chris Savage

    Parallax Engineering
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  • MarkovMarkov Posts: 19
    edited 2010-06-09 17:01
    right now you can buy same or similar fan to what is on the HB25--it is the same plus a second stage fan--that is a 3 and a 5-blade fan in series (mechanically) with a finger guard on one side (i believe--from the pic)

    you can buy one of these little hummers for $3.95 or a set of four installed in a 'mini-rack' meant for installing in server racks (4 mounted horizontally) for $9.95--instead of razing your HB25. the one on the HB25 measures about 1.6 inches (if recall correctly) and i expect this is where MPJA calls what they are selling a 1.5" fan--(could turn out to be a bit bigger fan but i expect the HB25 has one of the same stages - recall it was the 5 blade stage--not near our HB25 now)

    www.mpja.com (then select fans, then DC Fans, scroll...)

    the latter listing:
    "Product:
    4X DUAL FAN MASTER ASSEMBLY

    MFG: AVC for H/P
    P/N: DB0404812U
    Voltage: 12 VDC
    Current: 1.14A/subassembly
    CFM: 25+/subassembly
    Server fan unit has 4 removable dual 1-1/2” (40mm) 12V fan subassemblies. Each subassembly consists of a 3 blade fan mechanically mounted in series with a 5 blade fan. Both sets of fan leads brought out to a connector (NO Mate available). 2" leads. UL/CSA/TUV/CE listed


    Stock No.:
    15839 FN Price:
    $ 9.95"
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