240D25-17 Datasheet, PDF (10/12 Pages) List of Unclassifed Manufacturers – SOLID-STATE RELAYS

DATA SHEET
Form 859-990514
SOLID-STATE RELAYS
page 10/12
Applications
Tips (Continued)
Transformer Loads
Careful consideration should be given to the selection
of the proper SSR for driving a given transformer. Transformers
are driven from positive saturation of the iron core to negative
saturation of the core each ½ cycle of the alternating
voltage. Large inrush currents can occur during the first ½ cycle
of line voltage when a zero voltage SSR happens to turn on
during the positive ½ cycle of voltage when the core is
already in positive saturation. Inrush currents greater than
10 times rated transformer current can easily occur.
The following table provides a guide for selecting the
proper SSR for a given transformer rating.
Solenoid Valve and Contactor Loads
All Opto 22 SSRs are designed to drive inductive loads such as solenoid
valves and electromechanical contactors. The built-in snubber in each SSR
assures proper operation into inductive loads. The following table is a
guide in selecting an SSR to drive a solenoid or contactor.
120-Volt Coils
SSR CURRENT
RATING
SOLENOID
2-Amp
1-Amp
4-Amp
3-Amp
240-Volt Coils
CONTACTOR
NEMA Size 4
NEMA Size 7
120-Volt Transformers
SSR MODEL
TRANSFORMER
P or MP 120D2
100 VA
SSR CURRENT
RATING
2-Amp
4-Amp
SOLENOID
1-Amp
3-Amp
CONTACTOR
NEMA Size 7
NEMA Size 7
Z120D10
500 VA
120D3
100 VA
P or MP 120D4
250 VA
120D10 or 120A10
500 VA
120D25 or 120a25
1 KVA
120D45
2 KVA
240-Volt Transformers
P or MP240D2
200 VA
7240D10
1 KVA
120D3
200 VA
P or MP240D4
500 VA
Control Current Calculation
All Opto 22 DC controlled SSRs have a control circuit consisting of 1000 ohms in
series with an LED. Since 3 volts is required to turn on any SSR, the maximum current
required is (3 volt - 1 volt) divided by 1000 ohms which equals 2.0 mA. The 1 volt is subtracted
from the 3 volt signal because 1 volt is dropped across the LED. For higher control voltages,
an external resistor can be added in series with the control voltage to limit the control
current. To limit the control current to 2 mA, calculate the external resistor R_C = 500 (E_C- 3)
where E_C = the control voltage.
The DC control voltage range is 3–32 VDC. To calculate the control current for any
voltage within the 3–32 VDC range, use the formula:
240D10 or 240A10
1 KVA
240D25 or 240A25
2 KVA
240D45
4 KVA
480-Volt Transformers
I_C =
E_C - 1
1000
where R_C = zero.
SSR MODEL
480D10-12
480D15-12
TRANSFORMER
5-Amp Primary
5-Amp Primary
With a 5V control signal,
5-1
I_C = ₁₀₀₀ = 4 mA.
Opto 22 • 43044 Business Park Drive • Temecula, CA 92590 • Phone: [phone] • (800)321-OPTO • Fax: [phone] • Internet: www.opto22.com
Inside Sales: (800)452-OPTO • Product Support: (800)TEK-OPTO • [phone] • Fax: [phone] • E-mail: [e-mail] • FaxBack: (800)474-OPTO