Safety-control devices UZS.2
UZS.2 protection and control units are designed for the protection of three-phase asynchronous 0.55 kW to 5,5 kW electric motors used in pumping units. The UZS.2 unit consists of three modules: electronic phase sequence and decay sensor, thermal overcurrent circuit breaker and overcurrent circuit breaker in a control circuit.
The protection and control unit protects against the effects of:
- phase decay,
- (improper) phase sequence, (proper pump rotation),
- short-circuit in control system.
|Rated voltage supply
||3 x 400V, 50Hz, układ TN-C-S, TN-S
||1,2 A ÷ 25 A
|Device operation temperature
||-20oC ÷ +45oC
|Enclosure protection degree
The UZS.2 protection and control unit is designed for operation in moderate climate conditions, ambient temperature -10oC to +40oC, relative humidity up to 80% at 20oC, in the environment free of water and dust as well as of explosive, inflammable or chemically active gases and vapours. Altitude of the place of installation should not exceed 1 000 m a.s.l.
UZS.2 - design
The UZS.2 protection and control unit consists of electrical automation elements, switches and control equipment connected together to create a system. The unit is built into ABS and polycarbon enclosure with IP55 protection degree and of protection class II. UZS.2 can be hung on the wall or supporting structure. Power, receiving and control wires are fed through sealing glands located on the lower enclosure side.
Protections variety according to power
||Approximate maximum motor power
||Setting scope of overolad relay
height x width x depth mm
||1,8 ÷ 2,8 A
||230 x 140 x 125
||2,7 ÷ 4,2 A
||4,0 ÷ 6,2 A
||6,0 ÷ 9,2 A
||8,0 ÷ 12,0 A
||11,0 ÷ 16,0 A
||11,0 ÷ 16,0 A
||15,0 ÷ 20,0 A
||19,0 ÷ 25,0 A
UZS.2 - principle of operation
Protection against power circuit shorts in UZS.2 protection and control units is installed by the user himself. Its selection should be made according to the regulations and standards in force. For protection against phase decay and improper phase sequence a CKF.316 sensor and for protection against effects of short circuit in control circuit the S301 overcurrent switch is used. Protection against overload effects is ensured by an overcurrent switch based on thermo-bimetallic relay. Power is switched on by a rotary switch, then protection and control unit switches pump Smotor on (position "1"). The pump motor stops when the rotary switch is switched to "0" position.
When the red LED on the CKF module lights up after switching the power on, this indicates an improper phase sequence. So, the power line phase sequence on power input terminal should be changed, then proper rotation direction should be established in hand-operated position. When the circuit switches off during pump operation and a red LED on the CKF module lights up, this indicates that a significant line voltage drop occurred or phase failed. Remove the failure. After failure removal, the system resumes operation according to the rotary switch setting.