This is a shoplight, American Fluorescent Model No.: 234UTAH; LOT:1131 might refer to year 2011 week 31. Contains a ballast, Energy Pro WQ-1028-TP-1 dated 2011-07-07, attached by two screws and nuts. This fixture has only two holes for mounting control gear, spaced to hold one ballast 9.5 inches long. This fixture is short/shallow (interior height is one and one quarter inch, 1¼"), obstructing a common magnetic ballast.
(The usual residential rapid start two-lamp ballast height is at least 1½ inch. The usual lengths are 6.5 and 9.5 inch.)
This power unit WQ-1028-TP-1 is: quiet, short/shallow (low profile height less than 1¼ inch), low mass (lightweight). I guess this is an LC ballast, capacitive and inductive without transformer. It is low power factor (For Residential Use Only) and low ballast factor (Energy Saver). It operates one or two lamps in parallel. UL file number E254233 is assigned to JIAXING SONGLI ELECTRICAL EQUIPMENT CO LTD (Link to File FKVS.E254233).
This type of ballast (LC) is significantly smaller and lighter than a fully-magnetic (transformer and choke/inductor) ballast. A discussion about how an LC ballast and electronic starter works is found on icefoglights' Shoplight Ballast.
It is comparable to Seth11's "CDL M240120NR03" (Cordelia Lighting? JIMWAY INC E210609).
It is comparable to High Intensity's "DEAN"-branded "HFC-240-120-TS", also its label states "MINIMUN Starting Temp.:+50°F". (in High Intensity / Fluorescent Fixtures , in High Intensity / Ballasts) And Bluesvan has "DEAN HFC-240-120-LS1", nearly identical to HFC-240-120-TS. (Label indicates manufacturer is "WuXi Heng Feng Electronic Products Co., Ltd.". UL File Numbers E303474 and E256378 are assigned to WUXI HENGFENG ELECTRONIC PRODUCTS CO LTD, but not category Fluorescent Lamp Ballasts.) (Also "Energy Pro" brand appears on a "HFC 240 120 TS" label, posted by wsommariva on HandymanWire.)
It is comparable to arcblue's Keystone 240TPES and Pacific Ballast PN-240-TP.
Also Luminaire has Keystone 240TPES, which ey photographed uncovered to show its plain components.
measured operating power (single lamp)
F40T12 30W ,31A pf,8
F34T12 24W ,33A pf,6
F30T12 27W ,35A pf,65
F25T12 25W ,32A pf,63 (28 inch)
F20T12 21W ,3A pf,6
F17T8 24W ,37A pf,53
I am using this ballast on a timer (one start daily) with two two-foot F20T12 lamps. So far, it is working 3600 hours.
the other kind of "shoplight ballast" (transformer, rapid start, low ballast factor)
ProStandard 2xF40T12 LPF magnetic ballast (ProStandard TNC-234-6120-TP1)
Advance 'BenchLite' 2xF40T12 Ballast - RL-240-1-TP
Universal 2x F40T12 Ballast - 705-L-TC-P
Universal 2xF40T12 Ballast - 720-LR-TC-P ('SHOP LIGHT BALLAST')
Pacific Ballast 2xF40 RS Ballast - ES-240E-TP