Page 1 of 2 12 LastLast
Results 1 to 15 of 19
  1. #1
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default Tachometer on Hercus 9C

    My Hercus seems a little slow for cutting steel, so I wanted to check the rotational speed. Could have borrowed an optical tacho, but a cheap tacho display with sensor is $14 or less from eBay, so I thought I would hook one up.


    What Pic Note
    Buy the gizmo, work out the wiring.

    Chinese symbols on the 5 pins, and no doco.

    Had to search the web for part number,
    to find someone else's pinout diagrams
    IMG_0454.jpg Sensor has 3 wires,
    power is 2 wires,
    but pin4 on display unused!!!
    Sensor uses a small magnet.
    Lost the round one that came with it -
    flew off somewhere when testing on a
    high RPM spindle motor - had to improvise.
    Part of rare-earth magnet from a disk drive.

    Try to work out where to put it.
    Spindle take-up nut?





    Bull nose pin thingy?
    IMG_0455.jpg

    IMG_0457.jpg
    Smashed up the
    magnet holder
    with a hammer.
    Got a tiny little flat triangle!
    Seems to work OK on spindle take-up nut IMG_0456.jpg Middle speed ~350RPM
    Thought I would check the motor speed also IMG_0458.jpg Different magnet fragment
    but it was a bit more unreliable... IMG_0459.jpg

    IMG_0460.jpg

    IMG_0461.jpg
    turned magnet around and got expected RPM
    IMG_0463.jpg



    So, I might make a little box and mount this near the rear belt pulley, but I gotta work out a power supply
    (this lathe motor is 3phase without a neutral, so local 240v transformer is a challenge)



    Anyway, with my current motor pulley, these are my spindle speeds...

    Belt position back geared straight
    Right: 38 RPM 207 RPM
    Middle: 66 RPM 355 RPM
    Left: 117 RPM 629 RPM


    "Textbook of turning" says 750RPM max., so I guess I am close to the original speeds, but a bigger motor spindle would be handy

  2. #2
    BobL is online now Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,183

    Default

    You might like to see how I have mounted mine.
    https://metalworkforums.com/f189/t203548-tacho-hercus

    I've power mine from a 24V output available on my VFD and have done the same on my DP and WW lathe.

    With etc VFD able to run to 120Hz I can get up to 1500 rpm out of mine but as it's a plain bearing Hercus I only do this for very brief periods

  3. #3
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default

    Thanks Bob.


    My drive system and belts are quite horizontal:
    IMG_1688.jpg
    so I'm not sure I will mount my sensor vertically like that, as I was hoping to put a shelf or Perspex™ sheet over the top.


    VFD for 24V? Luxury!
    (My man cave has 3ø, so I'm using a fat 4-conductor cable straight to the switch & motor.)
    I'll eventually design a HV step-down power supply.

  4. #4
    BobL is online now Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,183

    Default

    Quote Originally Posted by nigelpearson View Post
    I'll eventually design a HV step-down power supply.
    On my mill I'm running the Tacho from an old Telstra 240V to 9V DC wall wart.

  5. #5
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default

    Quote Originally Posted by BobL View Post
    On my mill I'm running the Tacho from an old Telstra 240V to 9V DC wall wart.

    Hmmm. Across two of the 3ø cables? Not sure I trust the insulation in a plug pack at over 400V

  6. #6
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

    Default

    Don't you have any 240V PPs near the lathe???
    Kryn
    To grow old is mandatory, growing up is optional.

  7. #7
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default

    Quote Originally Posted by KBs PensNmore View Post
    Don't you have any 240V PPs near the lathe???
    Kryn
    No GPOs nearby, and I'm sick of extension cables in my messy space.

    Of course, I could just put a little "bike generator" on the motor v-belt

  8. #8
    BobL is online now Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,183

    Default

    Quote Originally Posted by nigelpearson View Post
    No GPOs nearby, and I'm sick of extension cables in my messy space.
    Some other possible solutions for messy spaces:
    Use a 240v extension cable on an OH flying fox cable, will be useful for a lot more than the Tacho
    Three 18650 3400 mAh Li-Ion rechargeable batteries will give you ~12V and will run the taco for ~100 hours.

  9. #9
    Join Date
    Jul 2011
    Location
    Adelaide
    Posts
    837

    Default

    Get yourself a transformer like this https://www.ebay.com.au/itm/TRANSFOR...frcectupt=true

    You can use two of the phases to drive it and get 12V out.

  10. #10
    Join Date
    Aug 2006
    Location
    Melbourne
    Posts
    1,105

    Default

    Mount an RCD Powerboard close by to the lathe and just run a plug pack as BobL suggested. You can you the extra power points for a work light and coolant later on.

    https://www.ebay.com.au/itm/Clipsal-RCD-Protected-485P4CB30-Socket-Outlet-250V-10A-30mA-safety-powerboard/324013193159?hash=item4b70b0f7c7:g:AoUAAOSwcqFdiLVi&frcectupt=true

  11. #11
    Join Date
    Jun 2013
    Location
    Tasmania
    Posts
    257

    Default

    You don't happen to have the wiring diagram you used for the tacho?

    As you know, the wiring diagram is non-existent with them as supplied and I've failed getting those to power up without blowing something on the board in the various internet searches I've used. I'd like to have a working one on my X3 mill but was reluctant to try again as I've killed two.

    Thanks.

  12. #12
    Join Date
    Aug 2006
    Location
    Melbourne
    Posts
    1,105

  13. #13
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default

    Quote Originally Posted by lamestllama View Post
    Get yourself a transformer like this https://www.ebay.com.au/itm/TRANSFOR...frcectupt=true

    You can use two of the phases to drive it and get 12V out.
    Thanks!


    I was sure I searched for 415V transformer before and found nada.
    (maybe I searched for 415V power supply)

  14. #14
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default

    Quote Originally Posted by Hornetb View Post
    You don't happen to have the wiring diagram you used for the tacho?

    As you know, the wiring diagram is non-existent with them as supplied and I've failed getting those to power up without blowing something on the board in the various internet searches I've used. I'd like to have a working one on my X3 mill but was reluctant to try again as I've killed two.

    Thanks.

    and, to save you searching through the thread Com_VC pointed us to, https://metalworkforums.com/attachme...2&d=1556859139


    "Source" on that is external power. Positive goes to both the display and one wire of the sensor. Try it with 12V battery before trying any sort of plug pack (which has to be DC, probably DC regulated. Not AC)
    Last edited by nigelpearson; 9th Jan 2020 at 07:04 PM. Reason: explained the woring diagram link

  15. #15
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default 12V from Three Phase

    After spending some more web search time, I finally found what I needed. A compact way to get 12V from high-voltage AC. $18 on eBay:

    https://www.ebay.com.au/itm/AC-380V-...UAAOSwNypdmGsE

    The search trick was realising that other countries have different voltages for three phase. Australia and UK 400 or 415V, USA 240/480V, Africa and half of Asia 380V. 380V seems the most common, so searching for that was fruitful.

    Not a perfect solution, and for safety I will use it with a fuse, but this seems tidier than a larger 3ø transformer.

Page 1 of 2 12 LastLast

Similar Threads

  1. Hercus #3A or #1 T&C smaller wheel guard and Hercus #3A wheel shaft pulley.
    By lamestllama in forum METALWORK - Machinery, Equipment, MARKET
    Replies: 8
    Last Post: 30th Aug 2019, 12:01 PM
  2. Huanyang 24v line and tachometer
    By TheNutter in forum METALWORK GENERAL
    Replies: 17
    Last Post: 13th Aug 2015, 10:31 PM
  3. Tachometer
    By nearnexus in forum METALWORK GENERAL
    Replies: 16
    Last Post: 17th Feb 2014, 09:56 PM
  4. Hercus 9" vs hercus 260 ????????
    By bitza500 in forum THE HERCUS AREA
    Replies: 1
    Last Post: 26th Jun 2009, 10:50 PM
  5. Hercus parts on Ebay from Hercus
    By bollie7 in forum THE HERCUS AREA
    Replies: 0
    Last Post: 8th Oct 2008, 02:59 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •