Fisher-Pierce Meter Socket Style Photocontrols
Earliest units produced by this organization were tube-powered types. The company's facilities existed in South Braintree, Massachusetts - a suburb about 15 miles south of Boston. Production of photocontrols probably began during the mid to late 1940's. Their pioneer photocontrols probably were of the meter socket type having four protruding prongs in a square formation on the rear of the control that plugged into the jaws of a round aluminum receptacle having the same physical positioning as an electric utility meter socket. These receptacles were usually mounted on the sides of poles or on crossarms. As with all photoelectric lighting controls, their phototube or light sensitive cell had to be facing between northeast and northwest. These round glass enclosed controls contained a lower amperage relay that activated a higher capacity one (usually rated at 30 amperes) so that strings of higher wattage streetlights could be controlled. Also within the glass photoelectric controller was the light-sensitive phototube. See the accompanying photo and illustration. These controls made it more convenient and efficient in operating series street lighting circuits. Instead of the manual method, the photocontrol automated these circuits by energizing the series circuit oil switch and other components necessary to run these street lighting loops.
Four position meter socket mounted Fisher Pierce photoelectric lighting controls are still made to this day, typically for replacement purposes. They are completely solid state and have a plastic backing on the rear of them. Most are rated 120 and 240 volts.
Up until approximately 1960 when Fisher Pierce completely discontinued tube-powered units and manufacture solid state controls as their standard, pre-1960 meter socket styles had metal backings. Usually the date and month of manufacture is stamped on the rear of the unit. Fisher Pierce's date coding up until about 1960 on all controls consisted of the digit(s) of the month followed by the last two digits of the year, separated by a slash mark, enclosed in a hexagon. Some units have more than one date code stamped on them. The original manufacturing date is the earliest; subsequent dates represent factory rebuild or repair dates. This procedure was also utilized on aluminum base twist lock Fisher Pierce photocontrols, which were made up until early 1960 and are discussed in more detail later. All meter socket photocontrols are painted medium gray inside with a clear face to expose the phototube (or photocell, after 1960) and nameplate data.
Upon examining Fisher Pierce tube-powered photocontrols, another clue to the approximate date of their manufacture is the week and year digit code lettered on the phototube itself. In small letters around the side of the tube's plastic base are two digits (the week of the year, 01 through 52) and last two digits of the year. This procedure can be used in identifying the age of other types of Fisher Pierce tube-powered controls, such as the "bell jar" and fixture or bracket mounted types as described below.
'Bell Jar' Photocontrols
These controls came into production not long after the meter socket types became commercially available. They are nicknamed "bell jar" controls by streetlight fans on account of their tall, rounded top, cylindrical, capsule-like appearance. See the photo of one that accompanies this text. All contained a photosensitive tube and the necessary other components, like the meter socket type. Bell jar controls were rated at 5 amperes for operating individual luminaries and 30 amperes for strings of fixtures. Unlike the meter socket type the bell jar units were rated in either of the two amperage classes.
Bell jar photocontrols were mounted into aluminum receptacle bases which had a bracket affixed to them that provided pole or crossarm mounting. Their glass covers had screw threading around their base, enclosing the control's components. Servicing or internal component replacement was accomplished by first unscrewing the glass cover from its mounting base. Loosening two setscrews inside and then pulling the component assembly up and out of its three-prong receptacle allowed access to the internal components or removal of the component frame. The physical orientation of these units' three prongs was different than that of other Fisher Pierce tube powered controls.
Bell jar controls were manufactured up until around 1960. Those that operated individual or multiple strings of streetlights were sometimes mounted at the very top of utility poles. Identifying their year of manufacture can be accomplished by carefully unscrewing their glass cover from their mounting base and looking for the month-year date stamped on the component's metal frame. It is also possible to obtain a clue of one's age by looking for the week-month numbers on the exposed phototube. Bell jar photocontrols were painted white on their exterior with an approximately 1-1/2 inch wide clear band around the unit's upper section to expose the light sensitive phototube.
After bell-jar controls were discontinued upgrading or replacement was accomplished in a number of ways. Some utilities replaced the entire unit with a simple bracket type photocontrol receptacle that accommodated a twist-lock unit. This was practical for operating individual lights, usually 1,000 watts load and under. Another method of upgrading was by first removing the glass cover and pulling out the internal component assembly, replacing it by a cast aluminum cover having a twist-lock receptacle on its top. This conversion kit had three wires from its base with a plug that inserted into the old triangular plug-in configuration. The cover was secured over the top of the bell jar housing bracket by the identical setscrew location that held the former tube-powered internal assembly into place.
This method of upgrading was practical for controls 1,000 watts load and less. 30-ampere Fisher Pierce bell jar units were converted in later years by meter socket style controls providing the necessary load for operating strings of streetlights. In some instances where the load control wire ran overhead to multiple lights controlled by a higher amperage unit, a special colored insulator on the pole's crossarm identified the street lighting wire so the lineman could readily notice it. Instead of the usual brown or white, these insulators usually had blue, green or yellow glazes.
Fixture Mounted Glass-Enclosed Photocontrols
These were somewhat smaller in size than the bell jar units and were typically mounted on the top portion of mercury and incandescent street lighting fixtures, providing individual luminarie operation. Other controls of this type had a larger mounting base with a bracket so it could be pole or crossarm mounted. Like the bell-jar units, their glass covers were painted white on their exterior with a clear band around their upper section to expose the unit's phototube. Similarly, nameplate data was affixed to the unit's cast aluminum base. These also had similar components as the meter socket and bell jar styles and were produced up until the late 1950s. The first ones probably were introduced about 1950 or so. Most were designed for 5-ampere load operation, however it is possible higher ampere units with bracket mounting probably were made for controlling multiple strings of streetlights.
Date of manufacture identification can be accomplished by removing the unit's glass cover and looking for the unit's month-year stamp on the control's mounting frame. Reconditioned and factory serviced units have later date(s); the earliest represents the original month/year of manufacture.
These photocontrols had three prongs in a triangular-like formation that plugged into a mating receptacle base. Installation was accomplished by inserting the component frame into the receptacle, then installing the glass cover over the unit. The cover was firmly held in place by snapping two curved copper hold-down clips positioned on each side of the control's base.
Since many mercury and incandescent luminaries were produced with individual, integral tube-powered controls of this type, upgrading them to twist-lock photocontrols was accomplished in either of two ways. The most commonly utilized conversion kit Fisher Pierce offered was one that was initially accomplished by unclipping the tube unit's glass cover, removing it and pulling the photocontrol frame out of its receptacle. This Fisher Pierce adaptor had three wires looping from its base, like the bell jar conversion kits with a plug that fitted into the old receptacle configuration. Upon inserting this plug into the control base, the cast aluminum adaptor was set into place and secured by the same two-hinged copper hold-down clips that secured the former glass cover.
Much less common and probably the earliest tube-powered replacement kits was a solid-state photocontrol mounted within an identical frame that housed the earlier tube type controls. These were likely made from 1958 through 1960. The plastic photocontrol was secured to the frame and internally soldered or wired to three prongs that fitted directly into the old style tube unit configuration. These conversion controls utilized the same style glass cover (or the one from the former tube-type) and covered over the control, framework and wiring by slipping it over the unit's metal frame and securing with the two copper clips that were on each side of the receptacle base. It is probable that this was a short-lived concept, since the aforementioned adaptor cap covers with the twist-lock receptacle on top were less complicated, smaller and made for easier photocontrol replacement.
Accompanying this text are photos from my collection which have the original adaptors attached to their luminaries, individual older controls, adaptors and catalog illustrations.
Twist-Lock Photocontrols
These were a revelation to those associated in the street lighting industry because they were much more compact and were totally solid state. Fisher Pierce manufactured a wide variety of twist lock units through the years and still does, to meet just about any customer requirement. Their configuration and method of attachment became an industry standard in 1959 so that all twist-lock photocontrols of competing manufacturers would fit the same mating receptacle.
Fisher Pierce solid state photocontrols were made commercially available during mid-1958. During that year their clear aperture window exposing the photocell was round, usually about 1/2 inch in diameter, although a few were made as large as one-inch. Their first solid state, plastic controls were painted light gray on their inside with blue lettering on top. Light gray internally painted units were standard for years. Aluminum bases on them were utilized until late 1959 or early 1960. The month and last two digits of the year of manufacture were stamped on the aluminum base bottoms. During late 1958 the company changed the photocell exposure window to a larger, rounded top design, sometimes referred to as the "tombstone" opening. This was a clear unpainted area inside the plastic cover. This configuration has been utilized since on most of their controls and today is of the same basic design. 1958 and 1959 twist lock units commonly had the identification: LINE, LOAD and NEUTRAL stamped on each appropriate prong. During 1960 this was discontinued, probably upon realizing that these photocontrols could only be inserted into their receptacles one correct way. Also during 1960 plastic photocontrol bases were utilized, replacing their former aluminum ones. During 1958 and 1959 the unit's serial number and manufacturing date appeared on the base. In 1960 the control's serial number and date code (for warranty purposes) was stamped on a thin aluminum strip clipped immediately below the photocell, in plain view through the aperture window. The first two digits represented the year and quarter the photocontrol's warranty expired, followed by a sequence of several numbers, which was its serial number. Fisher Pierce's standard warranty on photocontrols typically was two years from the date of manufacture. The warranty expiration date was represented by the last digit of the expiration year appearing first; followed by the second digit representing the quarter. For example, a photocontrol made in third quarter 1960 with a two year warranty (as most did) had a numerical identification strip starting with the number "2" (for 1962) followed by the number "3", representing the third quarter. This method can be used for identifying the manufacturing date of most of the company's photocontrols from 1960 through the late 1980's. After then, the month and year of manufacture was lettered on the paper nameplate label on the control's base. Exceptions are units produced as an option that had warranties that exceeded two years however these have been uncommon with electric utilities through the years due to their additional expense. Two-year units generally have been rather standard practice. Aluminum strips with this numerical identification were used on the slightly larger (original) size solid state, plastic covered photocontrols until about 1965. From 1966 until about l968 when this size unit was discontinued, a white paper label with the warranty date code and serial number was affixed immediately below the photocell, visible through the window opening. The same method was used of the smaller (today's size) units until early 197l. These were smaller units with 1000-watt ratings first manufactured during 1965. It was determined about late 1970 that sunlight exposure was causing these small paper strips to dry up and fall from the photocell's mounting frame, commonly with the numerical information on them indistinguishable. So, commencing during 1971 a paper label unexposed to light or the elements was placed on the units' plastic base with the appropriate numerical information. This practice continues at Fisher Pierce to this day. 1971 also represented a year of innovative change at Fisher Pierce. All earlier units were painted inside; during 1971 and continuing to the present Fisher Pierce photocontrols have been made in solid color plastic. On some of the earlier inside-painted controls, the paint inside was badly flaking away, creating a sometimes unsightly appearance and occasionally interfering with the internal mechanisms. It is probable, too, that the solid color units were less expensive to manufacture because the painting and preparation steps were eliminated from their production process.
In addition to the warranty code date key stamped on the 1971 through late 1980s paper base identification labels, the year of manufacture appears on the top of the control's case. From 1971 through 1979 the last digit of the unit's manufacture appears; from 1980 through the present the last two digits of the year are embossed upon the units' tops, all enclosed within a circle.
Specialty Fisher Pierce Photoelectric Controls
'Duo-Volt' 240 Volt Controls (6690 series)
These were introduced about 1962 and superceded the former Model 6700 which was a considerably larger, bulkier unit that fitted mounting surfaces up to 3-5/8 inches in diameter. It is probable this control was physically bigger in size because of the additional internal components required to adequately handle the higher voltage. It is not known when the Model 6700 was introduced but it was probably around 1960. It was a standard twist-lock type that had fairly straight sides like most other Fisher Pierce photocontrols as opposed to the flanged base version.
Duo-Volt photoelectric lighting controls were the same physical size as the standard 6650 and 6660 series that was commonplace then for 120 volt operation. The Duo-Volt model had an operating range from 105 to 285 volts, which made it applicable for many street lighting applications and were painted blue inside for identification purposes. The standard light gray 120-volt (105 to 130 volt operating range) 6650 and 6660's had applicable identification painted on their tops, with nameplate information, etc. The 6650s had blue painted lettering; the later 6660s had white lettering and the blue Duo-Volts also had white contrasting lettering. The Duo-Volt's warranty date code and serial number was stamped on a metal strip affixed to the photocell holder, immediately below the glass-enclosed photocell, in plain view through the unit's aperture window. From 1965 to 1968 similar identification appeared on a small white paper strip in the same location.
The Duo-Volt control continued in production until 1971, when the trade name for it was simply deleted physically from it and the nameplate data embossed in slightly raised lettering on top simply stated that the control was rated for 105 to 285 volts. During 1968 the somewhat larger style Fisher Pierce controls were replaced by the smaller units, introduced in 1965 for 120-volt operation and are about the same physical size as today's models. Some, if not all smaller size 1968 through early 1971 105-285 Duo-Volt controls were painted light gray inside, like the 120 volt ones, with white painted lettering on top. In 1971, when Fisher Pierce produced their photocontrol covers in solid-colored plastic, their 105-285 volt units still were light gray in most instances. Starting in 1973 their covers were solid blue and continue to be to this day, with raised identification lettering on top and serial number, warranty date code, etc., information appearing on a paper label on the unit's plastic base. Their paper base labels began to be utilized in 1971.
Photo-Feedback Photoelectric Lighting Controls
These were introduced about 1962 and were known as the 6650B series. These had the advantage of unrestricted physical orientation. The design of the 6650B places the photocell near the center of the unit where exposure to direct light of the sun could only occur only at dusk or dawn when maximum atmospheric filtering eliminated potentially harmful rays to the photocell itself. These units required north facing aperture window orientation, however Fisher Pierce stated in their day that any other direction positioning would be appropriate. Therefore, the 6650B could have been orientated in any direction to avoid the illumination effects of artificial light during nighttime; unaffected by extraneous light. The field of vision of the unit was adjusted by a screw adjustment at the base of the control.
Two differing aperture window variations of the photofeedback design were manufactured. The earliest had a rectangular opening approximately 1/2 inch high by 1-1/4 inches long, which allowed ambient light to filter into the unit's center where the photocell was positioned. These had a 500-watt load rating. The other had an approximately one-inch square opening, allowing more light to enter. The latter probably were among the later units and were rated at 500/1,000 watts load.
Photofeedback units were the same physical size as the smaller 120 volt, model #6660 series introduced in l965. The photo-feedback controls were made with a polycarbonate cover and all were painted red inside. As a testimonial to their sturdiness, like other 1960s Fisher Pierce photocontrols, a number of photofeedback controls are still in service in two Massachusetts communities served by municipal light departments. The photofeedback controls were manufactured until 1968. Serial number data appears on their base while nameplate information appeared in white raised lettering on the top of the controls.
Series 6650 Photoelectric Lighting Controls
These were usually 500 watt rated controls which were of the larger size that preceded the #6660 series in l965. The 6650 units were rated at 120 volts and had the advantage of being less expensive than their light gray 1000-watt load counterparts. The 6650s were ideal for installation on low wattage incandescent and mercury vapor fixtures 400 watts and less.
This economical control was popular in its day. Like all other Fisher Pierce photocontrols, except the Photo-feedback units, the 6650 had its photocell mounted immediately behind its aperture window, which was of the "tombstone" design. All 6650's were painted red internally and nameplate data was painted in white lettering on the top of the unit.
The first 6650 photocontrols were probably introduced in 1962 or a year earlier. They remained in production until about 1967. At that time photocontrol customers likely wanted more of the 1,000 watt load controls; also with the latter types becoming more commonplace, it likely was just as inexpensive to manufacture a 1,000 watt load unit as a lesser capacity unit.
Photos of Fisher-Pierce photocontrols
