Series RC1313

Resistor-Capacitor Networks

 

Applications

The circuit to be used is dependent upon particular situations. Either circuit may be enough protection for your needs. For extreme situations, both "Load" and "Contact" protection may be required.

 

Recommendations

• "Glow Discharges" caused by the ignition of gases between contacts. These develop at about 320 volts at about a 0.0003 inch gap range and can be sustained at a much wider gap range.
• "Arc Discharges" occur at much lower voltages, about 0.5 MV/cm. Minimum voltages and currents are necessary for "Arc Discharges" to be sustained. Contact material also plays a role in sustained "Arc Discharges". (see Table 1)

MATERIAL	MIN. VA Arcing Voltage	MIN. IA Arcing Current mA
Silver Gold Gold Alloy Palladium Platinum	12.0 15.0 19.0 16.0 17.5	400 400 400 800 700

The function of the RC network is to:

• Keep the voltage across the contacts below 300 volts. C ³ (I_L/300)²L
• Keep the rate of voltage change below 1 V/ms. C ³ I_Lx10^-6
• Keep the current below that described in Table 1.

Capacitors will restrict an instantaneous change in voltage. A capacitor, therefore, is useful to counter the destructive voltages generated at the switch contacts. When the contacts are closed, the capacitor is out of the circuit. As the contacts are opened any change in voltage is restricted by the capacitor if its value is large enough to restrict the voltage change to less than 1 V/ms.

A capacitor alone is not an ideal solution. When the contacts are open, the capacitor charges up to the supply voltage. As the contact is "made", an inrush of current results, limited only by a residual resistance, and damage may still result. For this reason, a resistor is configured in series with the capacitor. The higher the resistance value, the smaller the inrush current and the less effective is the capacitor. The voltage across the contacts when opened is equal to the load current x resistance (V = IR). It is recommended to keep V £ supply voltage. In this case, the maximum resistance of the network (R_N) will be equal to the load resistance (R_L).

The above formulas are recommended for determining the RC network parameters. They do not identify all of the subtleties but should serve as a guideline for effective results.

Resistor Specifications		Lead Specifications
Power (Watts) Voltage (VAC) Type 0.25 0.50 250 250 Carbon Comp. Carbon Comp. Resistor Tolerance: ± 10% or better		Solid Copperweld L S Dia. Min. Lead Length 0.709 1.040 1.260 0.562 0.886 1.130 .031 .031 .031 1.000 1.000 1.000

Dimensions and Ratings

RC1313
Cap. µF	Voltage DC   AC		Res. Value W	L in. (mm)	T in. (mm)	H in. (mm)	Size Code	UL-Recognized Part
0.10 0.10	200 630	125 250	22-1000 22-1000	.709  (18.0) 1.040  (26.5)	.295  (17.5) .335  (18.5)	.531  (13.5) .669  (17.0)	H N	Ö
0.25 0.25	200 630	125 250	22-1000 22-1000	.709  (18.0) 1.040  (26.5)	.295  (17.5) .394  (10.0)	.531  (13.5) .748  (19.0)	H O
0.50 0.50	200 630	125 250	22-1000 22-1000	1.040  (26.5) 1.260  (32.0)	.236  (16.0) .512  (13.0)	.591  (15.0) .866  (22.0)	L Q
1.00 1.00	200 630	125 250	22-1000 22-1000	1.260  (32.0) 1.260  (32.0)	.335  (18.5) .670  (17.0)	.669  (17.0) 1.360  (34.5)	N V	Ö

EFC will manufacture to any non-standard value and size. Please consult factory for special requirements.

 

RC1313 Catalog Nomenclature

RC

1313

EFR

-0N

-0.1

-06.3

-020

/

5

101

Application Option RC - R/C Network Dielectric Code 1313 - Metallized Polyester Case Code EFR - Epoxy Case - Flat - Radial Size Code See Dimensions and Ratings Table Capacitance (mF) See Dimensions and Ratings Table Voltage 2.0 - 200 VDC 4.0 - 400 VDC 6.3 - 630 VDC

Capacitance Tolerance 05 - ± 05% 10 - ± 10% 20 - ± 20% etc. Resistor Wattage 2 - 1/4 watt 5 - 1/2 watt 6 - 1.0 watt 7 - 2.0 watt Resistor Value (W) First 2 digits are significant figures, last digit is number of zeroes added (i.e. 101 = 100 ohms)

EFC will manufacture to any non-standard value and size. Please consult factory for special requirements.