13

MMK

Safety Precautions

Refer to Safety Precautions for All Relays.

■ Mounting

Make sure that the Relay is free from iron powder or iron core,

otherwise the iron dust may adhere to the Relay. As a result the

movable contact may not operate properly.

An arc may be generated between the contacts in switching

operation. Be sure to keep combustible objects away from the Relay.

If the arc will have a bad effect around the Relay, the use of a model

with a casing is recommended.

A model switching DC load incorporates an insulation base with a

small built-in permanent magnet. Be sure to keep magnets or ferrous

objects away from the permanent magnet, otherwise the capacity of

the maximum switching current may drop.

The PL Back-connecting Socket must be flush-mounted from the

surface of the panel.

To minimize the influence of heat, separate Relays from each other

by at least 20 mm for cooling when mounting multiple Relays

together.

Be sure to mount the Relay so that the movable contact is in the

downward direction.

■ Connection

• When connecting a load to the contact terminals of a model for

switching DC loads (“X” models), consider the polarity of the con-

tact terminals so that the generated arcs on the adjacent poles will

not collide. (For example, if the common connections of the Relay

are all positive or all negative, no arc collision will occur.)

• Use proper crimp terminals or 1.2- to 2-mm-dia. single-conductor

wire to connect screw terminals.

Screw Terminal Model

Do not bend the coil terminals, otherwise the coil wire may be dis-

connected. Make sure that the tightening torque applied to each ter-

minal is 1.27 N • m and the insertion force is 49 N for 10 s.

Solder Terminal Model

Make sure that Relay terminals are free of flux or other foreign sub-

stance before soldering the Relay terminals. Finish soldering the

Relay terminals quickly, otherwise the coil wire may be broken.

■ Circuits

• You cannot use single contact to demagnetize the set coil as shown

below.

• NC contacts can remain open for a few milliseconds when the reset

coil turns ON and OFF. NO contact can remain open for a few milli-

seconds when the set coil turns ON and OFF while the Relay is

latched. Design your circuits to allow for this.

• Do not allow voltage to be applied simultaneously to both the set

and reset coil. If voltage is applied simultaneously, the Relay will be

set.

• There is no reason to apply voltage to Latching Relays continu-

ously because they will latch properly with a single pulse of suffi-

cient width. Continuously applying voltage will only waste power.

• A model for DC loads incorporates a permanent magnetic for arc

suppression. Keep floppy disks away from the Relay, otherwise the

data on the floppy disk may be damaged.

• Arcing when switching DC power can cause nitric gas to be

generated. The case of the MM

@XKP contains holes to allow the

gas to escape. This, however, makes it possible for dust and dirt to

enter the case. Be sure to use the MM

@XKP in a suitable

environment.

■ Switching an AC Load with a

DC-switching Model (“X” Model)

DC-switching Relays (“X” models) use a magnet to extinguish arcs.

The polarity must be correct when you connect the switching section.

However, if you connect an AC load, the positive and negative poles

of the power supply alternate. This can cause short-circuits due to

the collision of arcs that occur when the Relay turns OFF.

Therefore, the switching capacity for an AC load is specified as 20 VA

or less to prevent short circuits caused by arc collisions.

Take sufficient caution if you switch an AC Load with a DC-switching

model (“X” models).

■ Refer to the technical guide on

your OMRON website for

technical descriptions and

FAQs on the product.

20 mm

min.

MMK

MMK

Normal mounting direction

Top

Bottom

Latching Relay coil

NC contact of the Relay

Load

MMK contact

(NC)

The contact

may fail to

hold itself.

Relay coil

In the interest of product improvement, specifications are subject to change without notice.

ALL DIMENSIONS SHOWN ARE IN MILLIMETERS.

To convert millimeters into inches, multiply by 0.03937. To convert grams into ounces, multiply by 0.03527.