APM110

Indicators. The unit is equipped with 5 indicators (LEDs) which indicate to the user the condition of the unit: 1. Load. Illuminated when the measurement crosses 5% of the measurement range. If the current flows the wrong way through the unit the indicator is NOT lit. 2. Ts. Illuminated when the measurement crosses 5% and is turned off when Ts expires. 3. Max. Illuminated when the Max limit is exceeded and the Tr timer is started. 4. Min. Illuminated when the Min limit is exceeded and the Tr timer is started. 5. Relay. Indicates the relay state; The LED is illuminated when the relay is ON, i.e. during normal operation. When an alarm is active, the relay is OFF and the Max- or Min- LED is lit showing which limit was exceeded and tripped. Max power range The unit is constructed for measuring currents up to 80 A. In the table below the recommended maximum ranges for standard supply voltages are shown. Unipower® APM110 3x380-3x500Vac Technical information The internal current sensor is linear up to 130A, but the current should be limited to 80A due to the maximum cable diameter of 10mm. The built-in current sensor is protected against current peaks of up to 500A Special versions The APM110 can be supplied for single phased applications also. A version which measures power after a frequency inverter may be provided on request. Technical Specifications Mechanical spec. Housing Upper part: Lexan UL94V-0 Lower part: Noryl UL94V-0 Mounting M36 for 35mm DIN rail CT dim: Max 10 mm lead-in Terminals: Max 16 A. Max 2,5 mm2 Protection class IP40 (housing). IP20 (connector). Temperature range -15 - +50 °C. Weight: Approx. 300g. Dimensions D 58 x B 70 x H 86 mm. Electrical spec. Supply / Range 3x380 to 3x500Vac Current range Internal max. 0-80 A (Surge: 500A/10sec.) External: N/5 C.T. Power range Max 70 kW using internal current sensor ϕ range: 0.2-1 Cosϕ Frequency range: 50 / 60 Hz. Consumption: 3VA Relay spec.: 250 VAC/5A. Control inputs: +8-30Vdc General Unipower APM110 is a „low-cost“ member of the Unipower family. The unit measures power from the formula: P = √3 x U x I x Cosϕ The primary function of the unit lies in the supervision of machinery driven by 3phase AC-motors. Unipower APM110 integrates a programmable Max. and Min. kW limit detector plus the support functions necessary to establish the efficient and compact supervision or control of various types of machinery such as pumps, fans and conveyor belts. Besides the functions Ts, Tr and hysteresis, the APM110 has a built-in current sensor that measures currents up to 80A. CE mark to: EN50081-1, EN61000-6-2, EN61010-1 Fig.4 Typical connection with internal sensor Page 4 Fig.5 Typical connection with external CT Page 1 Overview The basis of the unit is a specially developed 4quadrant multiplier which together with a precision current sensor makes it possible to use the unit for measuring loads from 0.01kW to 70kW. For larger loads an external CT must be used. The unit accepts crest factors up to 5 and is therefore applicable for measuring before frequency inverters. The built-in limits and timers etc. will be described in the following paragraphs. Measurement range internal sensor By means of a 3-digit switch [Range/Limit] a measurement range from 0.01kW to 9.99kW may be selected. If a larger range is needed, the chosen range may be multiplied by 10 by setting the switch [x10]. Using only the internal current sensor the maximum range is 70kW (See table on page 4). If a larger range is wanted an external CT (N/5A) is needed - N being the CT’s primary current. Measurement range ext. CT To set up the measurement range when using an ext. CT, a simple calculation is necessary: Ex: A measurement range of 100kW is wanted with a supply voltage of 3x400V. Choose a CT of 200A. The winding ratio of a 200/5A CT is 40. The unit must be set to 100kW/40 = 2.5kW for a measurement range of 100kW, i.e: Different from other units in the Unipower family the APM110 is programmed directly in kW. Since the unit accepts supply voltages from 380Vac to 500Vac and measures currents up to 80A directly, the unit is applicable in most of the world without special modifications to the supply voltage. The setting up of the unit and its functionality is described in the following. [Range] = Meas’ment range/CT winding ratio Max. Hyst’s band (10%) P [%] P = f(t) Tr Auto-Reset Max. limit = 100% 75% Min. Hyst’s band (10%) Auto-Reset 50% Min. limit 25% Ts Tr Tr Threshold Auto shut down Functions Figure 1 shows a typical AC-motor power consumption curve (ex. pump) immediately after power has been applied to the motor. At the bottom of the figure a bar is shown indicating the position of the relay (On/Off). The figure also shows the meaning of Ts, Tr and hysteresis. Max. Limit The Max. limit is always the same as the measurement range. Min. Limit The Min. limit is set from 20% to 80% of the measurement range. The limit is set in steps of 4% with the switch [Min. Limit]. By normal shut down of the motor no alarm is generated (Auto shut down). Ts: Start timer The start timer (Ts) is used for avoiding alarms at motor start. The Ts delay function is activated after the power consumption reaches 5%. When Ts expires, limits, hysteresis and Tr become active. If the consumption drops below 5%, the supervision is switched off again. Tr: Reaction timer When a limit is exceeded the corresponding Tr is activated. The limit must be exceeded for the duration Tr before the relay position is changed to Off. If the measurement drops below the limit before Tr expires the timer is reset. Auto Reset, Hysteresis Figure 1 shows how possible Max. and Min. hysteresis bands are placed relatively to the limits. The hysteresis equals 10% of the range and is fixed. Hysteresis is activated when an alarm is generated and the external reset is active (Input S1, Auto reset mode) Manual Reset An alarm may be reset either by pressing the key [Reset] or connecting the input S1 to 12V. 5% t Power On Relay On Fig. 1 Page 2 Alarm blocking Ts blocks alarms during startup; blocking of alarms after startup may be done by connecting S2 and/ or S3 to 12V. Ex. 1: If a short overload is expected a PLC-output or the like may be used to block alarms for a given time. Ex. 2: If only one limit is needed, the other may be blocked using S2 (Max limit) or S3 (Min limit). Choosing limits Deciding the Max. limit [P1] may be done in two ways: Theoretically or by measuring the actual load. Theoretically Md = P2 x 60 / 2πn, where Md: Torque where alarm should be given. P2: Corresponding shaft power. n: Revolutions in rev./min. P1 = P2 + Po. Po is the idle power of the motor. Measuring Choose a range larger than the expected consumption at the given load. 1. Measure Vref (0-10Vdc) with a voltage meter and calculate the actual kW value, or 2. Set Tr Max to 10 sec. Decrease the range gradually until the Max limit indicator is flashing. Start by decreasing the first digit and end with the last digit. When the actual load is known the Max. limit is set as wanted for the given application. The Min. limit is set in % of the Max. limit and may be determined the same way. Installation The unit is installed as shown in the schematics on p. 4 Voltage connection The unit automatically adapts to supply voltages from 3x380Vac to 3x500Vac. The phase order is of no importance, but it is IMPORTANT to measure the current in the same phase as connected to the units Terminal 1. Pay attention to the direction of the current. Control inputs The inputs S1, S2, S3 are isolated via optocouplers and are activated by means of a dcvoltage of 8-30V. The control voltage may be taken from Terminal 17. The inputs may also be activated from PLC outputs as shown in the schematics. Reference output Terminals 23 and 24 supply a voltage of 0-10Vdc proportional to the measured power (kW). 10Vdc equals the range. Note: Terminal 24 is connected to measurement Gnd formed by 3 pcs. 1Mohm resistors connected to the phases. I.e. no High Voltage, but connecting Terminal 24 to external equipment may result in measurement errors. Page 3