Photocontrol for electric lamps

• US 4,008,415 A
• Filed: 12/11/1974
• Issued: 02/15/1977
• Est. Priority Date: 12/14/1973
• Status: Expired due to Term

• Current Assignee: Electrotec de Occidente SA
• Original Assignee: Electrotec de Occidente SA
• Inventors: Diaz-Romo, Francisco Javier, De Avila-Serafin, Antonio
• Primary Examiner(s): Kominski, John
• Application Number:
  US05/531,835
• Time in Patent Office: 797 Days
• Field of Search: 315/360, 315/149-159
• US Class Current: 315/156
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

An improved photocontrol system for electrical lamps comprising the combination of photoelectric means responsive to the intensity of the ambient light for controlling the turning the lamps on and off, and an electronic timer for turning off the lamps at a preset time interval, after they have been turned on.

Claims

1. A photocontrol system, comprising:

a. circuit means having power supply terminals for connection with a source of electrical energy and load terminals for connection with an electrical load;

b. switch means connected in the circuit means to control supply of current to the load terminals;

c. electrical means controlling operation of said switch means;

d. solid state electronic timer means connected between the load terminals and comprising a pulse generator which generates pulses at a predetermined frequency, beginning when current is supplied to the load terminals, and counting means which count the pulses generated by the pulse generator and provide an output signal when a preset count has been reached after beginning counting;

e. control means connected to respond to said output signal by causing said electrical means to bring about opening of the switch means; and

f. photoelectric means respective to the intensity of ambient light to cause the electrical means to maintain the switch means open independently of said control means until the level of ambient light falls below a predetermined level,

whereby when said power supply terminals are connected with a source of electrical energy and the intensity of ambient light falls below said predetermined level, said photoelectric means automatically cause said switch means to close and remain closed until said preset count is reached or the intensity of ambient light once more reaches said predetermined level, which ever is sooner, whereupon said switch means are automatically opened and remain open until the intensity of ambient light falls once more below said predetermined level.

2. A system as claimed in claim 1, wherein the control means comprises a controllable semiconductor device and the photoelectric means comprises a resistive member connected in parallel with the controllable semiconductor device, the resistance of the resistive member falling to a low level when the level of ambient light reaches a high level so as to deprive the controllable semiconductor device of holding current.

3. A system according to claim 1 in which the electrical means is an electromagnetic relay.

4. A system according to claim 1 in which the electrical means is a bimetallic heat responsive relay.

5. A system according to claim 1 in which the electrical means is a solid state relay.