China manufacturer of magnetic ballasts for metal halide flood lights & hps flood lights

High Intensity Lamps such as the Sodium and Metal Halide lamps that are used in grow lights need a ballast to regulate the power supplied to them. Without a ballast to control the power to the lamp, it would simply draw massive amounts of power and instantly fail. This is why you need to match your 600 Watt Lamp with a 600 Watt HPS Ballast – so that the right level of power is supplied to the lamp and that the lamp itself is not damaged.

high-intensity discharge (HPS) high pressure sodium lamps require a ballast to limit current to the electrodes. Ballasts also provide the correct voltage for starting and restarting, and they adjust current to maintain light color and intensity over time. All ballasts suffer internal losses—typically 5 to 30 percent of the lamp wattage—that should be included in any calculation of potential savings, especially when switching from nonballasted sources such as incandescent lamps. Two main types of ballasts are now available: the newer electronic ballasts and the more common magnetic ballast.
HID Lamps have a band of operation at which they will perform to their optimum level, the gases within the lamp will ignite correctly (providing the intended colour of light) and no unnecessary damage is caused to the lamp. In a 600 Watt Sodium Lamp for example, this range is from 580-660 Watts. Any further power to the lamp and you risk damage and the colour rendition from the lamp will not be as intended. You may achieve higher overall light output from lamps that are overrun above this safe level, but it will be expensive both in terms of electricity used and the need to replace your lamps more often. It is therefore very important to provide consistent power to your lamp within the safe range of operation for that lamp.
Electronic ballasts can be made continuously dimmable, down to about 50 percent of full output power. This characteristic makes them more amenable to daylight harvesting than magnetic ballasts, which, at best, offer step-dimming down to one or two lower levels. Step-dimming to 50 percent of full power is common in warehouses and other irregularly occupied building spaces. Both electronic and magnetic HID ballasts lose efficiency at a similar rate as they are dimmed, so that when power has been reduced to 50 percent of full power, the lamps put out only about 35 percent of maximum light output. However, dimming any HID lamp, even with an electronic ballast, may lead to significant color-shifting, seriously limiting this capability in areas where color is of concern.