Insulation parts
Slot Separators for Double-Layer Windings
Slot separators sit inside the slot between the copper wires, at roughly half height, and separate two winding layers from each other.
The slot separator is closely related to the slot wedge. Both are long insulation profiles pushed axially into the slot. The difference is their position: the slot wedge closes the slot at its opening, while the separator sits in the middle of the winding and divides the bottom layer from the top layer.
This separation is needed wherever two coil sides share the same slot, typically in double-layer windings. If top and bottom layer belong to different phases, the insulation between them has to withstand the full voltage difference. The separator keeps both layers cleanly apart through insertion, forming and impregnation.
Because the separator takes up space inside the slot that would otherwise be available for copper, it is usually made from thinner material than the slot wedge. Besides the flat version, we also produce slot separators as a Z-profile.
Material and geometry
Suitable materials are flexible sheet insulation and laminates of classes B to H, such as NPN laminate, DMD laminate, Nomex 410 aramid paper or Mylar polyester film. The right choice depends on thermal class, voltage between the layers and the available slot cross-section.
Width, profile and length follow your slot geometry. Forming tools are made in our own tool shop, so new profiles are implemented within a few weeks.
Single source with slot liners and slot wedges
Slot separators are almost always installed together with slot liners and slot wedges. We supply all three parts for the same stator, matched to the slot geometry and in one delivery. Samples are available from a quantity of one, and production is certified to DIN EN ISO 9001 and DIN EN ISO 14001.
For a quote we need the slot geometry, the position of the separator in the slot, the required thermal class and the core length. Send us a drawing or sample part via the contact form.
Product view
Stator with slot separators at mid-slot height, flat or as a Z-profile
Frequently asked questions
What is the difference between a slot separator and a slot wedge?
Their position in the slot. The slot wedge closes the slot opening and holds the winding in place. The separator sits at roughly half height between the copper wires and divides two winding layers.
Why is a slot separator thinner than a slot wedge?
It sits in the middle of the winding and occupies space that would otherwise be used for copper. That is why it is usually made from thinner insulation material.
When is a slot separator needed?
When two coil sides share the same slot, typically in double-layer windings. If the layers belong to different phases, the separator has to insulate the voltage between them reliably.
Are slot separators available as a Z-profile?
Yes. Besides the flat version we produce slot separators as a Z-profile, each matched to your slot geometry.
More Products
Slot Wedges and Slot Closures
Slot wedges close the slots in rotor or stator after winding and are also called slot caps.
Learn more →
Slot Liners for Electric Motor Stators
Slot liners separate the winding from the core and prevent flashovers in the stator slot.
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NPN Laminate of Nomex and Polyester Film
NPN is a three-layer laminate of Nomex, polyester film and Nomex.
Learn more →Do you have a specific requirement?
Talk to us. We will find the right insulation solution.