soft start circuit for angle grinder - anyone done one?

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Hi,

I've got an antique angle grinder which does not have a soft start - as
a result the retainer siezes on and it's a right PITA.

Knowing modern grinders have softstarts built in, is it possible to
retrofit a softstart circuit into an older grinder?
The grinder is single phase 240 VAC and about 2kW. I've sent Makita an
email, but heard nothing back yet.

If it's not something easily built, does anyone know of a module which
can be added in from another model? links to part numbers, cct
schematics etc? All I've found googling are audio ccts - not single
phase power units.

Thanks,
Des

Re: soft start circuit for angle grinder - anyone done one?
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I was thinking something along the lines of a light dimmer type
circuit, with a suitably rated triac, turn the knob from zero to full
to turn it on.  Or modify it with a resistor/capacitor type
arrangement to simulate turning the knob from zero to full over a
couple of seconds when started. ?

Re: soft start circuit for angle grinder - anyone done one?

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Wimp, just get a good grip on the thing before turning on the power ;)

Yes I know they like to try jumping out of your hands

Solutions?  How technical are you?  

Series resistor shorted out by a timed relay?  Simple but mechanical.

Current surge limit thermistor as used in power supplies?  Bad because
they need a long cool-down period after use, or use a timed relay to
short the thermistor during use so it's cool for the next start.

Some sort of TRIAC based slow start?  Haven't seen one, but then I
haven't been looking for one either, it's a simple enough problem.
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If there's room, otherwise inline.

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Ouch, big enough :)
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Start by looking for a drill speed controller, and think of sending a ramp
voltage into whatever the speed wiper goes into, but it depends on the
circuit you start with.  

Grant.

Re: soft start circuit for angle grinder - anyone done one?
wrote:
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His complaint is that it tightens the blade to much, getting a grip has
nothing to do with it.


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Re: soft start circuit for angle grinder - anyone done one?

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wrote:
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learn to spell (s/to/too/)

Grant.

Re: soft start circuit for angle grinder - anyone done one?
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wrote:
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The extra o just wastes bandwidth just like this post (and your post)

Re: soft start circuit for angle grinder - anyone done one?
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This is the classic solution for a soft start. Doesn't even need a timed
relay.
The initial voltage drop causes the relay to delay until the motor comes up
to speed.

................. Zim



Re: soft start circuit for angle grinder - anyone done one?

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Maybe just try some anti-seize on the threads (& retainer face?). Loctite
makes a good anti-seize compound. Lots less work......



Re: soft start circuit for angle grinder - anyone done one?
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do it up tight before you turn it on.

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All the 100mm cheapies I've used had no such thing, I never used
the spanner just gripped the disc and turned it hand tight.  
after use it was still hand-tight.

If the disc slips at startup it will overtighten the nut.

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It's a big one then, you've got to get the nut really tight on those,
two-hand tight. You say it's old, perhaps you need to replace the
retainer nut and/or spindle. Does is look worn ?

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go to makita and grab the spare-parts diagrams, if it's not a feature
of the rotor their replacement part for the new models may fit yours.

⚂⚃ 100% natural


Re: soft start circuit for angle grinder - anyone done one?
try this...

http://www.pne.com.au/products/istart.shtml?gclid=CKvn8cnyl6gCFQlspAod62t3Cg

mark



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Re: soft start circuit for angle grinder - anyone done one?
On Thursday, April 7, 2011 6:31:13 PM UTC+5:30, Des Bromilow wrote:
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I have an endico angel grinder which doesn't require this so never tried this before.It is long lasting and durable.

http://www.endicopowertools.com/electric-angle-grinder.php

Re: soft start circuit for angle grinder - anyone done one?
On Thu, 5 Sep 2013 04:17:01 -0700 (PDT) snipped-for-privacy@gmail.com wrote in

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 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I'll take thing that a spammer would say for $100, Alex.

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Re: soft start circuit for angle grinder - anyone done one?
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<snip most of the spam>

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I wonder how much torque's required to grind an angel?

--  
Bob Milutinovic
Cognicom


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