Automatic switches AP-50

Automatic switches of the AP-50 series are designed to protect electrical installations, including asynchronous electric motors, from overload and short circuit, as well as for infrequent (up to 6 per hour) switching on and off of electric circuits or starting and stopping of electric motors.

AP-50 circuit breakers are designed to operate under the following conditions:

• at ambient temperatures from -40 ° (without dew and frost) to + 40 °;

• at a relative humidity of the surrounding air no more than 90% (temperature 20 °) and no more than 30% (temperature + 40 °);

• at an altitude of up to 1000 m;

• with vibration of the attachment points of the machine with a frequency of up to 25 Hz with an acceleration of no more than 0.7.

The machines of this series are not intended for operation under the following conditions: in an explosive environment, in an environment containing active gases and vapors that destroy metal and insulation, in an environment saturated with conductive dust and in places that are not protected against splashes of water , solar and radiant energy heating devices.

Automatic switches AP-50 are produced:

• bipolar for memorial voltage of alternating current up to 500 V at frequency 50 and 60 Hz and direct current up to 220 V and three-polar - for nominal voltage of alternating current up to 500 V;

• for nominal currents of phase overcurrent currents: 1.6; 2.5; 4; 6.4; ten; 16; 25; 40; 50 A; 63A.

• by the presence of phase overcurrent currents: with thermal and electromagnetic releases, only with thermal releases, only with electromagnetic releases, without releases — non-automatic switches for rated current 50 A;

• with intermittent currents of electromagnetic releases — 3.5 Azn, 8 Azn, 11 Azn.

• by the presence of overcurrent current in the neutral wire: without release — to the neutral wire, with release in the neutral wire. Automatic machines with overcurrent disconnection in the neutral wire are produced from the rated current of the phase releases of 16 A. The current of the continuous release mode in the neutral wire must not exceed 60% of the rated current of the phase;

• due to the presence of undervoltage releases 110; 127; 220; 380; 400 and 415 V AC at a frequency of 50 Hz with the possibility of closing the release coil for power from an external source;

• without undervoltage release, with undervoltage release;

• according to the presence and type of auxiliary contacts: without auxiliary contacts, with one switching, with two switching; an open design in a plastic housing and a dustproof design in an additional metal housing.

The structure of the symbol AP50 — 3MTHXXX:

AP50 — series circuit breaker; 3 — number of overcurrent releases: 3;

MT — overcurrent currents: MT — electromagnetic and thermal; X — additional releases: H — release from reduced voltage; D — shunt voltage release; O — maximum release of current in the neutral wire;

XX — climatic version and placement category: keys in a plastic shell — UZ, TZ, XL5; keys in a metal shell with degree of protection IP54 in accordance with GOST-U2, T2, HL5;

X — nominal current of overcurrent currents: 1 — 1.6; 2.5; 4.0A; 2 — 6.3; 10.0; 16.0A; 3 — 25.0; 40.0; 50.0; 63.0A.

Circuit breaker device AP-50 series

The AP-50 circuit breaker consists of the following main blocks: control mechanism. contact system, arc device, overcurrent releases.

Automatic switch AP — 50: a — general view; b — longitudinal section 1 — base; 2 — plastic case; 3 — fixed contact; 4 — movable contact; 5 — arc extinguishing plates; 6 — electromagnetic release; 7 — thermal release

The circuit breaker assemblies are located on a plastic base. It is closed above the base with a lid, below with a bottom. The control mechanism, built on the principle of free disconnection, ensures immediate opening of the contacts.

The interruption of the machine for overload currents and short-circuit currents is automatic and does not depend on whether the button is held or not held in the on position.

Block contacts are an independent unit kinematically connected to the movement of the movable main contacts.

Thermal tripping provides an inverse current-dependent response time in the overload zone, and electromagnetic tripping provides instantaneous tripping (interruption) in the short-circuit current zone.

Features of the AP-50 series automatic switches

The thermal releases of the AP-50 breaker at an ambient temperature of 25 ° C from a cold state, when an alternating single-phase current of 50 Hz passes simultaneously in all poles, allows, without shutdown for 1 hour, the operation of the machine at a current of 1.1 Azn and turn off the machine at a current of 1.35 Azn for no more than 30 minutes and at a current of 6Azn — for a time of 1.5 to 10 s.

The automatic machine provides reclosing after 2 minutes after being tripped by thermal release.

Intermittent current electromagnetic releases shut down the machine almost instantly.

Permissible deviation from the normal setting of the instantaneous operating (interrupting) current of electromagnetic releases:

• for nominal setting 3.5 In — deviation ± 15%;

• for nominal setting 8In — deviation ± 20%;

• for nominal setting 11In — + 15% — -30%.

Maximum switching capacity (PKS) and durability of AP-50 circuit breakers

Rated current of the edition 1.6 2.5 4.0 6.3 10 16 25 40 50 63 PKS, kA 380 V, 50 — 60 Hz 0.3 0.4 0.6 0.8 2.0 3.0 3.0 5.0 5.0 6.0 500 V, 50 — 60 Hz 0.3 0.4 0.6 0.8 1.5 1.5 2.5 2.5 2.5 3.5 220V DC 0.5 0.7 1.0 1.4 2.5 2.5 2.5 2.5 2.5 4.0 Wear resistance of VO cycles total 50000 Commutation * 50000 25000 20000

* — at rated current and voltage 380 V AC or 220 V DC

The current-time characteristics of the AP-50 circuit breakers are shown in Figs.

Protective characteristics of breakers AP -50: a — 50A, b — 40A, c — 25A, d — 16A, e — 10A, f — 6.4 A

The release of overcurrent in the neutral conductor ensures the deflection of the machine at a current equal to 100% of the rated current of the phase releases. Current tolerance +40 and -20%.

The machine switches are calibrated by the manufacturing plants at an ambient temperature of + 35 °.

The low voltage release does not prevent the machine from turning on when the voltage drops to 80% of nominal, and turns off the machine when the voltage drops to 35% of nominal or less.

The auxiliary contacts of the AP-50 breaker allow a continuous load of 1A, the limiting switching current is 10A.

Mechanical endurance of machines — 50,000 switching on and off.

Installation of automatic switches of the AP-50 series

During installation, the structure on which the machine is attached is leveled so that when the screws are tightened, the plastic body of the machine is not subjected to bending stresses.

The machine is installed in a vertical position with the inscription «On» up and secured to the structure with two screws. The screws securing the machine are tightened to failure. In this case, use a screwdriver of the appropriate size so that there are no chips in the plastic parts and no breakage of the slots in the screws.

The clamps of the main contacts of the machine ensure the connection to them of both copper and aluminum wires with a cross section of 6 to 10 mm2, and in the case of using a special tip - up to 25 mm2.

When connecting the outer wires, be careful not to allow the outer wires to create forces that tend to bend the terminal clamps. The wire is insulated with a length of 150 mm from the machine.

All connected clamps are tightly pressed against the output clamps. Joints are cleaned and scratches are removed.

The screw terminal blocks allow the connection of external wires with a cross-section of up to 1.5 mm2.

Before putting the cover on the machine, check for the presence of arc cameras in the compartments of the cover, and only then, putting the cover, pull it to the base with two screws.

At the end of the installation, the manual switching on and off of the machine in the off state is checked, in which there should be no blocking of the buttons, as well as contact of movable contacts with the plates of the arc - extinguishing chambers.

The AP-50 circuit breaker is designed to operate without repair or replacement of parts. The ground surfaces of the armature and the magnetic circuit of the low voltage release are coated with a thin layer of grease to prevent corrosion. The worn out machine gun is replaced with a new one.

Under normal operating conditions, the AP-50 circuit breaker is checked once a year and regardless of this after each trip from the short circuit current.