GP250 ENGINEERING DATA SHEET RELAY - LATCH 2 PDT, 2 AMP Polarized, latching hermetically sealed relay 2 PDT Contact arrangement Coil supply Direct current Qualified to SCC3602/010 PRINCIPLE TECHNICAL CHARACTERISTICS Contacts rated at 2 Amp / 50 Vdc Weight 11 grams max Dimensions of case 20.4mm x 10.4mm x 10.2mm Hermetically sealed, corrosion protected metal can. APPLICATION NOTES: 001 007 CONTACT ELECTRICAL CHARACTERISTICS Minimum operating cycles 100,000 cycles 100,000 cycles 100 cycles www.leachintl.com Contact rating per pole and load type Load Current in Amps @50Vdc resistive load inductive load (L/R=5ms) resistive overload 2 0.75 4 North America 6900 Orangethorpe Ave. P.O. Box 5032 Buena Park, CA 90622 USA Europe, SA 2 Rue Goethe 57430 Sarralbe France Asia-Pacific Ltd. 20/F Shing Hing Commercial Bldg. 21-27 Wing Kut Street Central, Hong Kong Tel: (01) 714-736-7599 Fax: (01) 714-670-1145 Tel: (33) 3 87 97 98 97 Fax: (33) 3 87 97 84 04 Tel: (852) 2 191 2886 Fax: (852) 2 389 5803 Data sheets are for initial product selection and comparison. Contact Leach International prior to choosing a component. Date of issue: 3/06 - 21 - Page 1 of 4 COIL CHARACTERISTICS (Vdc) GP250 CODE 06 12 26 Nominal operating voltage 6 12 26 Maximum operating voltage 7.3 14.8 32 Maximum latch or reset voltage at +125° C 4.6 9.8 18 Coil resistance in Ω ±10% at +25° C 40 150 720 GENERAL CHARACTERISTICS Temperature range -65°C to +125°C Dielectric strength at sea level - Contacts to ground, coils to ground 1000 Vrms / 50 Hz - Between coils, between open contacts 500 Vrms / 50 Hz Dielectric strength at altitude 25,000 m, all terminals to ground 350 Vrms / 50 Hz Initial insulation resistance at 100 Vdc >1000 M Ω Sinusoidal vibration 30 G / 75 to 2000 Hz Shock 100 G / 11 ms Maximum contact opening time under vibration and shock 10 µs Operate time at nominal voltage (including bounce) 4 ms max Release time 4 ms max Bounce time 2.5 ms max Contact resistance at rated current - initial value 50 mΩ max - after life 100 mΩ max Date of issue: 3/06 - 22 - Page 2 of 4 MOUNTING STYLES GP250 Ø3.2 0.6 10.4 MAX 00 DB DJ 0.76 A 10.2 MAX DE 6.35 Ø3.5 Ø3.5 8 MAX 27 ±0.2 27 ±0.2 4.9 DD DM = BC BD BJ BN = = = 10.5 ±0.1 27 32.9 MAX D 3.2 ±0.1 6.35 ±0.1 STUD ØM3 ØM3 ØUNC4.40 ØM2.5 ±0.1 ±0.1 32.9 MAX D BD BN 6.4 ±0.1 0.8 11 MAX 32.9 MAX DB DJ BC BJ HA ±0.1 8 MAX CONTRASTING BEAD 20.4 MAX ±0.1 D 9.5 7.3 10.5 9.5 3.15 ±0.1 C 29.8 MAX 33.55 ±0.25 DD DM DQ Ø3.5 8 MAX 4 x Ø 2.5 3.2 3.2 ±0.1 ±0.1 9.5 27 Ø5.5 B 25.2 ±0.2 27 ±0.2 ±0.2 B 32.9 MAX C Dimensions in mm Tolerances unless otherwise specified ±0.25 mm TERMINAL TYPES CONTRASTING BEAD CONTRASTING BEAD 5.08 5.08 2.54 E 5.4 MAX F Ø0.8 4.8 MAX TIN PLATED PINS Date of issue: 3/06 Ø0.8 Ø1.8 SOLDER HOOKS - 23 - Page 3 of 4 SCHEMATIC DIAGRAM GP250 BOTTOM VIEW, COIL ENERGIZED LAST RAZ A1 B2 B3 RAZ X2 A3 Y2 X1 + + Y1 A2 B1 CONTRASTING BEAD TERMINAL DESIGNATIONS ARE FOR REFERENCE ONLY AND DO NOT APPEAR ON STANDARD UNITS NUMBERING SYSTEM GP250 720 E 00 26V Basic series designation__________________________| | | | | 1-Coil Resistance_______________________________________| | | | 2-Terminal Types (E,F)______________________________________| | | 3-Mounting Style (00,DB,DJ,DE,DQ,DD,DM,HA,BC,BD,BJ,BN)__________| | 4-Nominal Voltage (06,12,26)_________________________________________| NOTES 1. Isolation spacer pads for PCB mounting available on request. 2. For other mounting styles or terminal types, please contact the factory. TYPICAL CHARACTERISTICS * Coil resistance/temperature change: See application note no. 001 Date of issue: 3/06 - 24 - Page 4 of 4 N°001 Application notes CORRECTION DUE TO COIL COPPER WIRE RESISTANCE CHANGE IN TEMPERATURE 1.8 Correction coefficient 1.6 1.4 1.2 1 0.8 0.6 -80 -30 20 70 Temperature ( °C) Nominal Resistance at 25°C 120 170 Nominal Resistance at 20°C Example: Coil resistance at 25°C: 935 ohms. What is it at 125°C? Correction coefficient on diagram is: 1.39 at 125°C. R becomes: 935x1.39=1299 Ohms Correction also applies to operating voltages Date of issue: 3/06 -1- Page 1 of 1 N°007 Application notes SUPPRESSOR DEVICES FOR RELAY COILS The inductive nature of relay coils allows them to create magnetic forces which are converted to mechanical movements to operate contact systems. When voltage is applied to a coil, the resulting current generates a magnetic flux, creating mechanical work. Upon deenergizing the coil, the collapasing magnetic field induces a reverse voltage (also known as back EMF) which tends to maintain current flow in the coil. The induced voltage level mainly depends on the duration of the deenergization. The faster the switch-off, the higher the induced voltage. All coil suppression networks are based on a reduction of speed of current decay. This reduction may also slow down the opening of contacts, adversly effecting contact life and reliability. Therefore, it is very important to have a clear understanding of these phenomena when designing a coil suppression circuitry. Typical coil characteristics On the graph below, the upper record shows the contacts state. (High level NO contacts closed, low level NC contacts closed, intermediate state contact transfer). The lower record shows the voltage across the coil when the current is switched off by another relay contact. The surge voltage is limited to -300V by the arc generated across contact poles. Discharge duration is about 200 mircoseconds after which the current change does not generate sufficient voltage. The voltage decreases to the point where the contacts start to move, at this time, the voltage increases due to the energy contained in the NO contact springs. The voltage decreases again during transfer, and increases once more when the magnetic circuit is closed on permanent magnet. Operating times are as follows: Time to start the movement 1.5ms Total motion time 2.3ms Transfer time 1.4ms Contact State Date of issue: 6/00 -8- Page 1 of 4 Types of suppressors: Passive devices. The resistor capacitor circuit It eliminates the power dissipation problem, as well as fast voltage rises. With a proper match between coil and resistor, approximate capacitance value can be calculated from: C = 0.02xT/R, where T = operating time in milliseconds R = coil resistance in kiloOhms C = capacitance in microFarads The series resistor must be between 0.5 and 1 times the coil resistance. Special consideration must be taken for the capacitor inrush current in the case of a low resistance coil. The record shown opposite is performed on the same relay as above. The operation time becomes: - time to start the movement 2.3ms - transfer time 1.2ms The major difficulty comes from the capacitor volume. In our example of a relay with a 290 Ω coil and time delay of 8 ms, a capacitance value of C=0.5 uF is found. This non polarized capacitor, with a voltage of 63V minimum, has a volume of about 1cm3. For 150V, this volume becomes 1.5 cm3. Date of issue: 6/00 -9- Page 2 of 4 The bifilar coil The principle is to wind on the magnetic circuit of the main coil a second coil shorted on itself. By a proper adaptation of the internal resistance of this second coil it is possible to find an acceptable equilibrium between surge voltage and reduction of the opening speed. To be efficient at fast voltage changes, the coupling of two coils must be perfect. This implies embedded windings. The volume occupied by the second coil reduces the efficiency of the main coil and results in higher coil power consumption. This method cannot be applied efficiently to products not specifically designed for this purpose. The resistor (parallel with the coil) For efficient action, the resistor must be of the same order of magnitude as the coil resistance. A resistor 1.5 times the coil resistance will limit the surge to 1.5 times the supply voltage. Release time and opening speed are moderately affected. The major problem is the extra power dissipated. Semi-conductor devices The diode It is the most simple method to totally suppress the surge voltage. It has the major disadvantage of the higher reduction of contact opening speed. This is due to the total recycling, through the diode, of the energy contained in the coil itself. The following measurement is performed once again on the same relay. Operation times are given by the upper curve: - time to start the movement 14ms - transfer time 5ms These times are multiplied by a coefficient from 4 to 8. The lower curve shows the coil current. The increase prior to NO contact opening indicates that the contact spring dissipates its energy. At the opening time the current becomes constant as a result of practically zero opening speed. Due to this kind of behavior, this type of suppression must be avoided for power relays. For small relays which have to switch low currents of less than 0.2 A, degradation of life is not that significant and the method may be acceptable. Date of issue: 6/00 - 10 - Page 3 of 4 The diode + resistor network It eliminates the inconvenience of the resistor alone, explained above, and it limits the action of a single diode. It is now preferred to used the diode + zener network. The diode + zener network Like the resistor, the zener allows a faster decurrent decay. In addition it introduces a threshold level for current conduction which avoids the recycling of energy released during contact movement. The lower curve on the opposite record demonstrates those characteristics. Voltage limitation occurs at 42V. The two voltages spikes generated by internal movement are at lower levels than zener conduction. As a result, no current is recycled in the coil. The opening time phases are as follows: - time to start the movement 2.6ms - total motion time 2.4ms - transfer time 1.4ms The release time is slightly increased. The contacts' opening speed remains unchanged. Date of issue: 6/00 - 11 - Page 4 of 4