Power control application guide

Pick the control by load type first, then by line power and load configuration.

Constant resistance elements

Nichrome, Kanthal, Calrod

Resistance nominally constant: less than 50% change versus temperature.

Line power	Load configuration	Phase angle	Zero fire	On/off
Single phase	Line-to-line or line-to-neutral	18D 18TB 18TBP	18DZ 11DZ-P	11D
Three phase	Balanced or delta connected loads, isolated from ground	18E	18EZ 11EZ-P	11E
Three phase	Grounded and/or unbalanced loads	18E-SW	—	—

Quartz tubes, T-3 lamps, Some infrared panels

High hot-to-cold resistance ratio: causes high inrush currents when elements are cold.

Line power	Load configuration	Phase angle	Zero fire	On/off
Single phase	Line-to-line or line-to-neutral	18D-H	—	—
Three phase	Balanced or delta connected loads, isolated from ground	18E-H	—	—
Three phase	Grounded and/or unbalanced loads	18E-SW	—	—

“Glo-Bar”, direct coupled

Resistance increases as elements age.

Line power	Load configuration	Phase angle	Zero fire	On/off
Single phase	Line-to-line or line-to-neutral	18D-H	—	—
Three phase	Balanced or delta connected loads, isolated from ground	18E-H	—	—
Three phase	Grounded and/or unbalanced loads	18E-SW	—	—

Heating elements driven from the secondary winding of a transformer

Inductive load with initial current inrush.

Line power	Load configuration	Phase angle	Zero fire	On/off
Single phase	Line-to-line or line-to-neutral	18D-SW	—	—
Three phase	Balanced three phase transformers	18E-SW	—	—
Three phase	Scott-T connected or unbalanced transformers	18E-SW	—	—

Magnets, Fields, Electrolytic cells

Resistive: load resistance nominally constant. Inductive: DC fields.

Line power	Load configuration	Phase angle	Zero fire	On/off
Single phase	DC power required	36D	—	36D
Three phase	DC power required	36E	—	36E

Replacing mercury relays, replacing SSRs, extruders, molding machines

On/off control of constant resistance electric heating elements.

Load configuration	Product
Single phase, constant resistance load	Model 11DZ
Three phase, constant resistance load	Model 11EZ

A dash means the control method is not offered for that combination.