Explanation of Electric Parameters for Solenoids
Dear Customer:
With regard to DC solenoids, hydraulic solenoid valve, solenoid
water valve, solenoid pump, etc, the relations between force and
resistance, current, voltage, power, enameled wire size, number
of windings of enameled wire, stroke, etc. are as follows:
- The shorter the stroke is, the bigger the force is. When inquiring
force, you must mention the stroke, because they are directly
relevant.¡£
- Generally speaking, the greater the power, the greater the force,
the two are of approximately direct ratio. But when power reaches
a certain level that solenoid approaches magnetic saturation,
the force increase little.
- If the resistance, current and voltage vary while the power
and coil remain the same, the force remains.
- a. If the coil resistance is kept unchanged when increasing
the number of windings with bigger size wire, the force will increase.
But if the original coil is already fully wound, the enameled
wire can't be changed, otherwise, the coil will be too bigger
to fit into the iron shell.
b. Increasing the number of windings with the same size enameled
wire only results in decreased force, because the negative effect
on the force of the resistance increase outweighs the positive
effect of the increase of the winding number.
c. Changing the enameled wire size (the resistance being changed)
but keeping the power (P= U2/R£»R¡¢U being
unchanged, but keeping P), we will get unchanged force.
- Operation time determines power, that is, if the operation time
continues a long period of time, the power can't be set too big,
otherwise, solenoid will be damaged by overheating.
For example: if customer selects SDO-0837L model solenoid, requiring
a stroke of 5mm, 500-g force, not mentioning size and power, we
may offer SOD-0837L already in storage in stead of winding for a
new solenoid, so as for a quick sample delivery, for instance, selecting
the solenoid of 36 ohm. After the customer has received the product,
they power it with regulated power supply, and adjust the voltage
(stroke set at 5mm). The force will increase with the voltage increase,
and the solenoid will heat up increasingly apparently. When the
force reaches 500g, the voltage is 24V. This means that SDO-0837L
is able to produce a force of 500g when power is set 16W(242/36=16),
stroke 5mm. If the customer use 12V power supply, the resistance
will be changed to 9 ohm in order to reach the same force while
keeping the 16W power (R=U2/W=122/16=9). If, at 16W power, the solenoid
produces more heat than customer permits or its limiting temperature
rise value(usually ambient temperature +65° or the current exceeds
that customer permits, a bigger sized solenoid shall be selected
to avoid that overheating.
The adoption of above methods will reduce the number of sample
delivery due to resistance changes.
For high sample success rate, customers are kindly requested of
the following conditions for solenoid use.
Maximum stroke, force requirement, voltage (or current and resistance),
expected life (total operation times within operational life), application
purpose (for what equipment), and other information that can be
offered.
R & D Department of Shenzhen Zanty Electronics
Co. Ltd
An ISO9001 & TS16949 Certified Manufacturer of
Solenoid, Solenoid Pump, Solenoid
Valve and Relays with UL, cUL, TUV, CQC Mark.
Sep. 12, 2002
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