Shop OBEX P1 Docs P2 Docs Learn Events
Repost: Soft start clutch — Parallax Forums

Repost: Soft start clutch

ArchiverArchiver Posts: 46,084
edited 2003-06-27 20:31 in General Discussion
Hmm..the initial post seems to have vaporized.

My application uses an electric clutch attached to a gasoline motor-
add 12 volts, clutch engages. The problem is that it engages so hard
that breakages are occurring. Has anyone an idea how to slowly
engage this device- It is "currently" being activated by a MOSFET
that is driven by an opto and a bs2p output. Any ideas are
appreciated.

Tim

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-06-27 16:21
    I think you need to look at the mechanical problems here first.
    1 What are you running off the engine
    2 What is the starting torque of this device
    3 What is the clutch rated at
    4 What is breaking
    5 What RPM is the motor running at
    6 Most motors have air flaps for keeping the motor at a constant RPM
    load/noload

    And yes you may be able to ramp up the voltage with slippage and heating and
    breaking

    Larry Gaminde


    Original Message
    From: "ohiotim2" <tweaver@i...>
    To: <basicstamps@yahoogroups.com>
    Sent: June 27, 2003 8:06 AM
    Subject: [noparse][[/noparse]basicstamps] Repost: Soft start clutch


    > Hmm..the initial post seems to have vaporized.
    >
    > My application uses an electric clutch attached to a gasoline motor-
    > add 12 volts, clutch engages. The problem is that it engages so hard
    > that breakages are occurring. Has anyone an idea how to slowly
    > engage this device- It is "currently" being activated by a MOSFET
    > that is driven by an opto and a bs2p output. Any ideas are
    > appreciated.
    >
    > Tim
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-06-27 16:30
    You can use a PWM function, start with a low pulse width and slowly
    increse it.

    With hardware, you can insert a choke in series, when applied power,
    the choke will limit the current until it saturates.
    Inductance of the choke could be defined as;

    V=L*di/dt
    simplifying, L (henries)=Voltage applied*time/Current
  • ArchiverArchiver Posts: 46,084
    edited 2003-06-27 20:14
    I wonder what the current draw will be when not completely engaged (electro
    magnet)

    Larry Gaminde
    Original Message
    From: "Jim Forkin" <jjf@p...>
    To: <basicstamps@yahoogroups.com>
    Sent: June 27, 2003 12:31 PM
    Subject: RE: [noparse][[/noparse]basicstamps] Repost: Soft start clutch


    > You need to ramp the voltage up very slowly to allow the clutch to slip.
    Do
    > this with an integrator circuit, however, some clutch designs will not
    > engage slowly but instead have an on/off type of engagement. This is
    > typical of the type used on automotive air conditioner compressors. In
    that
    > case, shock is absorbed by the belt stretch/slippage. Another approach,
    you
    > may need to soft couple to your motor using a rubber coupling which will
    > absorb some shock. Or, change to v belt coupling and adjust the tension to
    > allow some slippage on engagement. This is one reason that centrifigal
    > clutches are used in these types of applications so that engine speed is
    > increasing and starting to drive the load and when speed comes up high
    > enough to support the load, the clutch is fulling engaged. It also slips
    > when the load speed exceeds the drive speed. If you can engage the clutch
    > at a low speed and then increase engine speed it may solve your problem.
    >
    > jim
    > http://www.geocities.com/jimforkin2003/
    >
    >
    >
    Original Message
    > From: ohiotim2 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=8XMtxg7-ZrrEgxQqH5eU-oQkKeeaQ30cCmim0W9IUoK0QuOpO-ezRp6MKvoj1oc2XV1KVkVb9_wB8CMuUeDh]tweaver@i...[/url
    > Sent: Friday, June 27, 2003 11:07 AM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Repost: Soft start clutch
    >
    >
    > Hmm..the initial post seems to have vaporized.
    >
    > My application uses an electric clutch attached to a gasoline motor-
    > add 12 volts, clutch engages. The problem is that it engages so hard
    > that breakages are occurring. Has anyone an idea how to slowly
    > engage this device- It is "currently" being activated by a MOSFET
    > that is driven by an opto and a bs2p output. Any ideas are
    > appreciated.
    >
    > Tim
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    > Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-06-27 20:31
    You need to ramp the voltage up very slowly to allow the clutch to slip. Do
    this with an integrator circuit, however, some clutch designs will not
    engage slowly but instead have an on/off type of engagement. This is
    typical of the type used on automotive air conditioner compressors. In that
    case, shock is absorbed by the belt stretch/slippage. Another approach, you
    may need to soft couple to your motor using a rubber coupling which will
    absorb some shock. Or, change to v belt coupling and adjust the tension to
    allow some slippage on engagement. This is one reason that centrifigal
    clutches are used in these types of applications so that engine speed is
    increasing and starting to drive the load and when speed comes up high
    enough to support the load, the clutch is fulling engaged. It also slips
    when the load speed exceeds the drive speed. If you can engage the clutch
    at a low speed and then increase engine speed it may solve your problem.

    jim
    http://www.geocities.com/jimforkin2003/


    Original Message
    From: ohiotim2 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=-mHeb2oeR8tqmr4UX55QicQEg8f5XcsWV69qpYPVxt3JrQVhRMAHJM7USpyqDEwuVCfvzI7C1jcxpawt0723]tweaver@i...[/url
    Sent: Friday, June 27, 2003 11:07 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Repost: Soft start clutch


    Hmm..the initial post seems to have vaporized.

    My application uses an electric clutch attached to a gasoline motor-
    add 12 volts, clutch engages. The problem is that it engages so hard
    that breakages are occurring. Has anyone an idea how to slowly
    engage this device- It is "currently" being activated by a MOSFET
    that is driven by an opto and a bs2p output. Any ideas are
    appreciated.

    Tim


    To UNSUBSCRIBE, just send mail to:
    basicstamps-unsubscribe@yahoogroups.com
    from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.


    Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Sign In or Register to comment.