Re: starter solenoid pull in voltage

service@xxxxxxxxxxxxxxxx wrote:

John Popelish wrote:

service@xxxxxxxxxxxxxxxx wrote:

Thanks for your reply John,

The reason I asked is I did a study with 2000pcs of 12V starter
solenoid. 1000pcs has pull in voltage of 4.5V and the other 1000pcs
has 6V. Both batch went through 420A in rush for 1ms.

A few of the 4.5V got stuck while none of the 6V got stuck.

I was thinking may be increasing the pull in voltage will increase the
in rush current that that starter solenoid can withstand.

A few out of 2000 is a pretty small sample. I can't imagine the
mechanism that would couple pull in voltage and sticking, unless it is
the return spring force (lower for the lower pull in voltage units, if
everything else is similar). That spring force is what breaks the
contacts apart after they spot weld.


The 4.5V and 6V lots are identical starter solenoid with the exception
of the stated pull in voltage. I think the manufacturer adjusted the
weight of the plunger to get the different pull in voltage. This has
the same effect as changing the spring force, correct?

So what you're saying is that the reason the 6V lot did not have any
sticks was because it has a higher spring force(due to lower plunger
weight, everything else being equal) thus a higher force to break the
contacts?

Thanks again for your inputs.

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the reason the 4.5 are getting stuck is because there is insufficient
impact created from the velocity generated from the coil to clamp the
the contacts together soon enough before the induction of the motor (starter) can cause damage to the contacts and thus weld them.

a Peak and Hold driver circuit most likely could work here, the
same theory as used in fuel injectors for the same reason to prevent
sticking of the mechanism in response.
because you also have to worry about the initial force required to get
the core moving.

we have some special motor started relays at work that have dual coils in them that use a low level AUX contact mounted on the body.
the idea is when the relay is in the OFF state, both coils are connected., when the core reaches almost to the close point the AUX contacts open one coil. this gives us a low but effective holding current.
when making contactors to be compact, its important to think about
these things. they also make electronic Peak and Hold types.




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Relevant Pages

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  • Re: starter solenoid pull in voltage
    ... The reason I asked is I did a study with 2000pcs of 12V starter ... I was thinking may be increasing the pull in voltage will increase the ... in rush current that that starter solenoid can withstand. ...
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  • Re: starter solenoid pull in voltage
    ... The reason I asked is I did a study with 2000pcs of 12V starter ... I was thinking may be increasing the pull in voltage will increase the ... in rush current that that starter solenoid can withstand. ...
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  • Re: starter solenoid pull in voltage
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