W.e. anderson div., dwyer instruments, inc, Circuit information for reed switch protection – Dwyer L10 User Manual

Page 2

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©Copyright 2011 Dwyer Instruments, Inc.

Printed in U.S.A. 11/11

FR# 82-440851-00 Rev. 2

CIRCUIT INFORMATION FOR REED SWITCH PROTECTION

READ INFORMATION BELOW BEFORE INSTALLING YOUR NEW REED SWITCH CONTROL!

Exceeding the current capacity of this Reed Switch control may cause FAULTY OPERATION! Be aware of the inductive and capacitive or lamp loads you may be placing on
you Reed Switch Control. The circuits below outline possible solutions to preventing overloads due to inrush or surge currents exceeding maximum or when the switch current
and product of the lamps (low “cold” resistance) is outlined below. Failure to follow these measures to protect Reed Switch Contacts may cause the contacts to weld together
or result in premature wear.

Possible Circuit Solutions Indicated by Dashed Lines

W.E. ANDERSON DIV., DWYER INSTRUMENTS, INC.

P.O. BOX 358 • MICHIGAN CITY, INDIANA 46361 U.S.A.

Phone: 219/879-8000

www.dwyer-inst.com

Fax: 219/872-9057

e-mail: [email protected]

Inductive Loads
Possible causes
An electromagnetic relay, electromagnetic solenoid,
electromagnetic counter with inductive component as
circuit load.

Capacitive Loads
Possible causes
A capacitor connected in series or parallel with Reed
Switch control. In a closed circuit, a cable length (usually
greater than 50m [162.5 ft.]) used to connect reed switch
may also introduce static capacitance.

Lamp Loads
Possible causes
A tungsten filament lamp load.

DIODE SUPPRESSION

DIODE

INDUCTIVE

LOAD

PIV DIODE > V

REED

SWITCH

REED

SWITCH

USED IN

AC CIRCUITS

VARISTER

VARISTER PROTECTION

INDUCTIVE

LOAD

RC SUPPRESSION

R

C

INDUCTIVE PROTECTION FOR

CABLE LENGTH CAPACITANCE

LOAD

REED

SWITCH

Cable Length

over 50 meters

[162.5 ft.]

REED

SWITCH

RESISTOR PROTECTION

FOR CAPACITIVE LOAD

SURGE LIMITER FOR

CAPACITANCE IN SERIES

REED

SWITCH

CURRENT LIMITING RESISTOR

IN SERIES

CURRENT LIMITING RESISTOR

IN PARALLEL

REED

SWITCH

REED

SWITCH

INDUCTIVE

LOAD

REED

SWITCH

SWITCH

[uf]

10

C

R

10*I

(1+50/E)

SWITCH

2

C

LOAD

SWITCH

SWITCH

LOAD

C

R

L =0.5~5 mH

P

+V

R

A

P

L

R

A

+V

R = 50~500 Ohms

R

B

P

L

L = 0.5~5 mH

P

+V

R

L

R

R

V-0.12 R

L

2

+V

R

L

5R > R

L

R

MAINTENANCE/REPAIR
Upon final installation of the Series L10, no routine maintenance is required. The
Series L10 is not field serviceable and should be returned if repair is needed. Field
repair should not be attempted and may void warranty.

WARRANTY/RETURN
Refer to “Terms and Conditions of Sales” in our catalog and on our website.
Contact customer service to receive a Return Goods Authorization number before
shipping the product back for repair. Be sure to include a brief description of the
problem plus any additional application notes.

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